Herb & supplement monograph

Grapefruit Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by ·Updated July 2026
What is this page for?

First and foremost: how Grapefruit interacts with medications. The heart of this page is the interaction list — every drug Grapefruit is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Grapefruit is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Grapefruit Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, Grapefruit drug interactions pose a genuine and often serious risk, and the chance of a clinically significant interaction is high for people taking many common medications. The large majority of listed interactions are rated major, and many are documented in well-controlled human studies rather than theory alone.

Interactions deserving the most attention

Grapefruit reliably raises blood levels of statins and calcium channel blockers, which can amplify side effects such as muscle problems or low blood pressure. It also boosts levels of the transplant drug cyclosporine, the seizure medicine carbamazepine, methadone, and certain benzodiazepines, and in large amounts it can add to the heart-rhythm risk of QT-prolonging drugs. Less widely known, it can work the other way and lower levels of some medicines, such as the active form of clopidogrel, weakening their intended effect.

What the rest of the list means

This wide reach comes from a shared mechanism: grapefruit blocks an enzyme the body uses to clear many medications, an effect that can last two days or more, and it also affects a transporter that helps some drugs get absorbed. That is why one fruit touches so many different medicines, though the strength of the effect varies from drug to drug.

Check your medications against Grapefruit

Based on HelloPharmacist’s Grapefruit interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Grapefruit

990 medications have a known interaction with Grapefruit, graded by severity. Select any drug for the full evidence-based detail.

776 major interactions. These combinations can be clinically significant — best avoided, or used only with close professional supervision. Always check with your pharmacist before combining them with Grapefruit.

2,830 drugs
Ado-trastuzumab EmtansineKadcyla
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Ado-trastuzumab Emtansine interaction Ado-trastuzumab Emtansine drug page: uses, dosage & side effects
AbemaciclibVerzenio
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Abemaciclib interaction Abemaciclib drug page: uses, dosage & side effects
Abiraterone
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Abiraterone interaction Abiraterone drug page: uses, dosage & side effects
Abiraterone AcetateYonsa, Zytiga
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Abiraterone Acetate interaction Abiraterone Acetate drug page: uses, dosage & side effects
AcalabrutinibCalquence
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acalabrutinib interaction Acalabrutinib drug page: uses, dosage & side effects
Acetaminophen, Aspirin, CaffeineExcedrin, Excedrin Extra Strength, Excedrin Migraine
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Aspirin, Caffeine interaction
Acetaminophen, Butalbital, CaffeineEsgic, Esgic Plus, Fiogesic, Fioricet, Repan, Tecnal +1 more
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Butalbital, Caffeine interaction Acetaminophen, Butalbital, Caffeine drug page: uses, dosage & side effects
Acetaminophen, Butalbital, Caffeine, CodeineEsgic with Codeine, Fioricet w/ Codeine
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Butalbital, Caffeine, Codeine interaction
Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, PhenylephrineHycomine Compound
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine interaction
Acetaminophen, Caffeine, CodeineGesic C15, Gesic C30, Gesic C8, Lenoltec 1, Lenoltec 2, Lenoltec 3 +1 more
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Caffeine, Codeine interaction
Acetaminophen, Caffeine, Codeine, SalicylamideCodalan No.1, Codalan No.2, Codalan No.3
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Caffeine, Codeine, Salicylamide interaction
Acetaminophen, Caffeine, DihydrocodeineDHC Plus, Panlor DC, Panlor SS
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Caffeine, Dihydrocodeine interaction
Acetaminophen, Caffeine, IsomethepteneMigralam
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Caffeine, Isometheptene interaction
Acetaminophen, Caffeine, PyrilamineMidol Max Strength Menstrual
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Caffeine, Pyrilamine interaction
Acetaminophen, Chlorpheniramine Maleate, Dextromethorphan HbrVicks Formula 44M Cough, Cold & Flu Relief
Major Dextromethorphan (robitussin Dm, Others)

Grapefruit juice can increase blood levels of dextromethorphan, potentially increasing the effects and adverse effects of dextromethorphan.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine Maleate, Dextromethorphan Hbr interaction
Acetaminophen, Chlorpheniramine, Codeine, PhenylephrineColrex
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine interaction
Acetaminophen, Chlorpheniramine, DextromethorphanCoricidin II Extra Strength Cold and Flu
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine, Dextromethorphan interaction
Acetaminophen, Chlorpheniramine, Dextromethorphan HydrobromideCoricidin HBP Maximum Strength Flu
Major Dextromethorphan (robitussin Dm, Others)

Grapefruit juice can increase blood levels of dextromethorphan, potentially increasing the effects and adverse effects of dextromethorphan.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine, Dextromethorphan Hydrobromide interaction
Acetaminophen, Chlorpheniramine, Dextromethorphan, PhenylpropanolamineMulti Symptom Cold Relief
Major Dextromethorphan (robitussin Dm, Others)

Grapefruit juice can increase blood levels of dextromethorphan, potentially increasing the effects and adverse effects of dextromethorphan.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine, Dextromethorphan, Phenylpropanolamine interaction
Acetaminophen, Chlorpheniramine, Dextromethorphan, PseudoephedrineChildren's Tylenol Cold Plus Cough, Tylenol Cold Ex Strength
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine, Dextromethorphan, Pseudoephedrine interaction
Acetaminophen, Chlorpheniramine, Guaifenesin, Phenylephrine, SalicylamideRhinogesic GG
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine, Guaifenesin, Phenylephrine, Salicylamide interaction
Acetaminophen, Chlorpheniramine, PhenylephrineAlka-Seltzer PLUS, Histex SR, Protid
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine, Phenylephrine interaction
Acetaminophen, Chlorpheniramine, Phenylephrine, SalicylamideRhinogesic, Rhinogesic JR
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine, Phenylephrine, Salicylamide interaction
Acetaminophen, Chlorpheniramine, PhenylpropanolamineAlumadrine, Conex, Sinadrin Max Strength, Sinulin
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine, Phenylpropanolamine interaction
Acetaminophen, Chlorpheniramine, Phenylpropanolamine, OpiumHista-Derfule
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine, Phenylpropanolamine, Opium interaction
Acetaminophen, Chlorpheniramine, Phenylpropanolamine, PhenyltoloxamineNorel Plus
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine, Phenylpropanolamine, Phenyltoloxamine interaction
Acetaminophen, Chlorpheniramine, PseudoephedrineAlka-Seltzer PLUS Liquid Gels, Children's Tylenol Cold, Codimal, Comtrex, Extra Strength Tylenol Allergy Sinus, Lorsin +3 more
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Chlorpheniramine, Pseudoephedrine interaction
Acetaminophen, DextromethorphanTylenol Cough Ex Strength
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Dextromethorphan interaction
Acetaminophen, Dextromethorphan, Doxylamine, PseudoephedrineVicks NyQuil
Major Dextromethorphan (robitussin Dm, Others)

Grapefruit juice can increase blood levels of dextromethorphan, potentially increasing the effects and adverse effects of dextromethorphan.

Read the full Grapefruit + Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine interaction
Acetaminophen, Dextromethorphan, Guaifenesin, PhenylephrineConar-A
Major Cytochrome P450 3a4 (cyp3a4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full Grapefruit + Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine interaction
Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

  • Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
  • Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
  • Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
  • No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

  • Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
  • Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
  • Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

  • Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
  • Each drug listed above links to the full report for that exact Grapefruit combination — clinical detail, likelihood, evidence level, and citations.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
The big picture

The kinds of drugs Grapefruit affects

Every type of medication (drug category) Grapefruit is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 62 drug categories Grapefruit interacts with
Amiodarone (cordarone)Artemether (artenam, Paluther)BenzodiazepinesBuspirone (buspar)Calcium Channel BlockersCarbamazepine (tegretol)Carvedilol (coreg)Celiprolol (celicard)Cisapride (propulsid)Clomipramine (anafranil)Clopidogrel (plavix)Cyclosporine (neoral, Sandimmune)Cytochrome P450 3a4 (cyp3a4) SubstratesDextromethorphan (robitussin Dm, Others)EstrogensEtoposide (vepesid)HalofantrineHmg-coa Reductase Inhibitors ("statins")Methadone (dolophine)MethylprednisoloneOrganic Anion-transporting Polypeptide Substrates (oatp)Praziquantel (biltricide)Qt Interval-prolonging DrugsQuetiapine (seroquel)QuinidineScopolamine (transderm Scop)Sildenafil (viagra)Tacrolimus (prograf)Terfenadine (seldane)Ticagrelor (brilinta)Aliskiren (tekturna, Rasilez)Budesonide (entocort, Uceris)CaffeineColchicineCytochrome P450 1a2 (cyp1a2) SubstratesCytochrome P450 2c19 (cyp2c19) SubstratesCytochrome P450 2c9 (cyp2c9) SubstratesEmpagliflozin (jardiance)ErythromycinFexofenadine (allegra)Fluvoxamine (luvox)Itraconazole (sporanox)Levothyroxine (synthroid, Others)Losartan (cozaar)Nadolol (corgard)Nilotinib (tasigna)Oxycodone (oxycontin)Pitavastatin (livalo)Prasugrel (effient)PrimaquineRivaroxaban (xarelto)Saquinavir (fortovase, Invirase)Sertraline (zoloft)Sunitinib (sutent)Tadalafil (cialis)TalinololTheophyllineTolvaptan (samsca)Warfarin (coumadin)Acebutolol (sectral)Amprenavir (agenerase)P-glycoprotein Substrates
Amiodarone (Cordarone)

Grapefruit juice can increase blood levels of amiodarone, potentially increasing the effects and adverse effects of amiodarone.
Clinical research shows that grapefruit juice inhibits metabolism and increases absorption of amiodarone. Grapefruit juice increases amiodarone plasma levels by 50% and peak concentration by 84%.

Likelihood Probable Evidence B
Artemether (Artenam, Paluther)

Grapefruit juice can increase blood levels of oral artemether, potentially increasing the effects and adverse effects of artemether.
Clinical research shows that grapefruit juice increases the levels of oral artemether by 90% to 250% in healthy males.

Likelihood Likely Evidence B
Benzodiazepines

Grapefruit juice might increase blood levels of some oral benzodiazepines, potentially increasing the effects and adverse effects of these drugs.
Clinical research shows that grapefruit juice can increase plasma triazolam concentrations. Repeated consumption of grapefruit juice greatly increases triazolam concentrations and prolongs the half-life, probably due to inhibition of cytochrome P450 3A4 (CYP3A4). Some studies show that grapefruit juice, particularly when taken in large quantities, reduces the clearance and increases the maximum blood levels, area under the plasma concentration curve (AUC), and duration of effect of midazolam. However, there is no effect on intravenous midazolam. Grapefruit juice has also been shown to increase the maximum blood levels and duration of effect of diazepam, but the clinical significance of this is not known. This interaction does not appear to occur with alprazolam.

Likelihood Likely Evidence B
Buspirone (Buspar)

Grapefruit juice can increase blood levels of buspirone, potentially increasing the effects and adverse effects of buspirone.
Clinical research shows that grapefruit juice increases absorption and plasma concentrations of buspirone.

Likelihood Likely Evidence B
Calcium Channel Blockers

Grapefruit juice can increase blood levels of oral calcium channel blockers, potentially increasing the effects and adverse effects of these drugs.
Clinical research shows that grapefruit juice increases absorption and plasma concentrations of amlodipine, nifedipine, nisoldipine, verapamil, felodipine, nimodipine, nicardipine, diltiazem, pranidipine, nitrendipine, and manidipine, This interaction is likely the result of the inhibition of intestinal metabolism of these drugs by CYP3A4, although some research suggests grapefruit may alter plasma drug levels by reducing the rate of gastric emptying. Consuming grapefruit juice 1 liter daily increases steady state concentrations of verapamil by as much as 50%. However, some references dispute the clinical relevance of the interactions with amlodipine, diltiazem, and verapamil. Other research in healthy individuals suggests plasma levels of felodipine and nifedipine are not affected when given intravenously. There is considerable interindividual variability in the effect of grapefruit juice on drug metabolism, which might account for inconsistent study results. In healthy older adults, the hemodynamic response to felodipine plus grapefruit juice might be influenced by altered autonomic regulation. In older healthy adults, a single dose of grapefruit juice and felodipine enhanced the blood pressure-lowering effects of felodipine. However, after a week of grapefruit juice and felodipine (steady state), the hypotensive activity was reduced, possibly due to compensatory tachycardia. Research indicates it is necessary to withhold grapefruit juice for as long as 3 days to avoid interactions with felodipine and nisoldipine.

Likelihood Likely Evidence B
Carbamazepine (Tegretol)

Grapefruit juice can increase blood levels of carbamazepine, potentially increasing the effects and adverse effects of carbamazepine.
Clinical research shows that grapefruit juice increases absorption and plasma concentrations of carbamazepine.

Likelihood Likely Evidence B
Carvedilol (Coreg)

Grapefruit juice can increase blood levels of carvedilol, potentially increasing the effects and adverse effects of carvedilol.
Clinical research shows that grapefruit juice increases the bioavailability of a single dose of carvedilol by 16%.

Likelihood Likely Evidence B
Celiprolol (Celicard)

Grapefruit juice can decrease blood levels of celiprolol, potentially decreasing the clinical effects of celiprolol.
In human research, taking grapefruit juice within two hours of celiprolol appears to decrease absorption and blood levels of celiprolol by approximately 85%. This interaction is due to grapefruit-induced inhibition of organic anion transporting polypeptide (OATP). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction.

Likelihood Probable Evidence B
Cisapride (Propulsid)

Grapefruit juice can increase blood levels of cisapride, potentially increasing the effects and adverse effects of cisapride.
Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of cisapride. According to the cisapride prescribing information, grapefruit juice is contraindicated in patients taking cisapride.

Likelihood Likely Evidence B
Clomipramine (Anafranil)

Theoretically, grapefruit juice might increase blood levels of clomipramine, potentially increasing the effects and adverse effects of clomipramine.
Case reports have shown that clomipramine trough levels increase significantly after the addition of grapefruit juice to the therapeutic regimen.

Likelihood Probable Evidence D
Clopidogrel (Plavix)

Grapefruit juice can decrease blood levels of the active metabolite of clopidogrel, thereby decreasing the antiplatelet effect of clopidogrel.
Clopidogrel is an antiplatelet prodrug that is metabolized primarily by cytochrome P450 2C19 (CYP2C19) to form the active metabolite. A small clinical study shows that taking grapefruit juice with clopidogrel decreases plasma levels of the active metabolite by more than 80% and impairs the antiplatelet effect of clopidogrel. This effect is possibly due to grapefruit-induced inhibition of CYP2C19.

Likelihood Probable Evidence B
Cyclosporine (Neoral, Sandimmune)

Grapefruit juice can increase blood levels of oral cyclosporine, potentially increasing the effects and adverse effects of cyclosporine.
Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of cyclosporine. The mechanism of action is unclear. However, there is no effect on intravenous cyclosporine.

Likelihood Likely Evidence B
Cytochrome P450 3A4 (Cyp3A4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.
Clinical research shows that grapefruit juice can inhibit CYP3A4 metabolism of drugs, causing increased drug levels and potentially increasing the risk of adverse effects. When taken orally, effects of grapefruit juice on CYP3A4 levels appear to last at least 48 hours. Grapefruit's ability to inhibit CYP3A4 has even been harnessed to intentionally increase levels of venetoclax, which is metabolized by CYP3A4, in an elderly patient with acute myeloid leukemia who could not afford full dose venetoclax. The lower dose of venetoclax in combination with grapefruit juice resulted in serum levels of venetoclax in the therapeutic reference range of full dose venetoclax and positive treatment outcomes for the patient.
Professional consensus recommends the consideration of patient age, existing medical conditions, additional medications, and the potential for additive adverse effects when evaluating the risks of concomitant use of grapefruit juice with any medication metabolized by CYP3A4. While all patients are at risk for interactions with grapefruit juice consumption, patients older than 70 years of age and those taking multiple medications are at the greatest risk for a serious or fatal interaction with grapefruit juice.

Likelihood Likely Evidence B
Dextromethorphan (Robitussin Dm, Others)

Grapefruit juice can increase blood levels of dextromethorphan, potentially increasing the effects and adverse effects of dextromethorphan.
Clinical research shows that grapefruit juice can inhibit cytochrome P450 3A4 (CYP3A4) metabolism, causing increased dextromethorphan levels.

Likelihood Probable Evidence B
Estrogens

Grapefruit juice can increase blood levels of estrogens, potentially increasing the effects and adverse effects of estrogens.
Clinical research shows that grapefruit increases the levels of endogenous and exogenous estrogens by inhibiting cytochrome P450 3A4 (CYP3A4) enzymes. Grapefruit juice increases exogenously administered 17-beta-estradiol by about 20% in females without ovaries and ethinyl-estradiol in healthy females.

Likelihood Probable Evidence B
Etoposide (Vepesid)

Grapefruit juice can decrease blood levels of etoposide, potentially decreasing the clinical effects of etoposide.
Clinical research shows that grapefruit juice decreases the absorption and plasma concentrations of etoposide. There is some evidence that grapefruit juice co-administered with oral etoposide can reduce levels of etoposide by about 26%. Grapefruit juice seems to inhibit organic anion transporting polypeptide (OATP), which is a drug transporter in the gut, liver, and kidney. Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction.

Likelihood Probable Evidence B
Halofantrine

Grapefruit juice can increase blood levels of halofantrine, potentially increasing the effects and adverse effects of halofantrine.
Clinical research shows that grapefruit juice inhibits cytochrome P450 3A4 (CYP3A4) metabolism, which increases halofantrine levels and peak concentration, as well as a marker of ventricular tachyarrhythmia potential.

Likelihood Probable Evidence B
Hmg-Coa Reductase Inhibitors ("Statins")

Grapefruit juice can increase blood levels of statins that are metabolized by cytochrome P450 3A4 (CYP3A4), potentially increasing the effects and adverse effects of these statins. Additionally, grapefruit juice might interfere with the bioavailability of statins that are substrates of organic anion transporting polypeptides (OATP).
Clinical research shows that grapefruit juice inhibits metabolism and increases absorption and plasma concentrations of statins that are metabolized by CYP3A4. These include lovastatin, simvastatin, and atorvastatin. Keep in mind that there is considerable variability in the effect of grapefruit juice on drug metabolism, so individual patient response is difficult to predict.
Some statins, including pravastatin, fluvastatin, pitavastatin, and rosuvastatin, are not metabolized by CYP3A4. However, grapefruit juice might still affect the bioavailability of these statins. These statins are substrates of OATP. Grapefruit juice can inhibit OATP. Therefore, grapefruit juice may reduce the bioavailability or increase drug levels of these statins depending on the type of OATP. However, grapefruit juice affects OATP for only a short time. Therefore, separating drug administration by at least 4 hours is likely to avoid this interaction.

Likelihood Likely Evidence B
Methadone (Dolophine)

Grapefruit juice can increase blood levels of methadone, potentially increasing the effects and adverse effects of methadone.
Clinical research shows that grapefruit juice inhibits the metabolism of methadone, increasing methadone levels and peak concentrations. In one case, a 51-year-old male taking methadone 90 mg daily and no other medications was found unresponsive. The patient reported drinking grapefruit juice 500 mL daily for 3 days prior to the event. Methadone is a substrate of cytochrome P450 3A4 (CYP3A4), and grapefruit juice-induced inhibition of CYP3A4 is the likely cause of this interaction.

Likelihood Probable Evidence B
Methylprednisolone

Grapefruit juice can increase blood levels of methylprednisolone, potentially increasing the effects and adverse effects of methylprednisolone.
Clinical research shows that grapefruit juice can increase the plasma concentration of orally administered methylprednisolone. Grapefruit juice 200 mL three times daily given with methylprednisolone 16 mg increased methylprednisolone half-life by 35%, peak plasma concentration by 27%, and total area under the curve by 75%.

Likelihood Likely Evidence B
Organic Anion-Transporting Polypeptide Substrates (Oatp)

Grapefruit juice can decrease levels of drugs that are substrates of OATP.
In vitro and clinical research show that consuming grapefruit juice inhibits OATP, which reduces the bioavailability of oral drugs that are substrates of OATP. Various clinical studies have shown reduced absorption of OATP substrates when taken with grapefruit, including fexofenadine, acebutolol, aliskiren, celiprolol, levothyroxine, nadolol, and pitavastatin. Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction.

Likelihood Likely Evidence B
Praziquantel (Biltricide)

Grapefruit juice can increase blood levels of praziquantel, potentially increasing the effects and adverse effects of praziquantel.
Clinical research shows that grapefruit juice can inhibit cytochrome P450 3A4 (CYP3A4) metabolism of praziquantel. Plasma concentrations of praziquantel can increase by as much as 160% when administered with 250 mL of commercially available grapefruit juice.

Likelihood Probable Evidence B
Qt Interval-Prolonging Drugs

Grapefruit or grapefruit juice, especially if consumed in large amounts, can cause additive QT interval prolongation when taken with QT interval-prolonging drugs, potentially increasing the risk of ventricular arrhythmias.
Clinical research in healthy volunteers shows that drinking 6 liters of grapefruit juice over 6 hours prolonged the QTc by a peak amount of 14 milliseconds (ms). This prolongation was similar to the QT prolongation caused by the drug moxifloxacin. In individuals with long QT syndrome, a smaller dose of grapefruit juice, 1.5 liters, resulted in a greater peak QTc prolongation of about 30 ms. The effect of smaller quantities of grapefruit juice on the QT interval is unclear.

Likelihood Probable Evidence B
Quetiapine (Seroquel)

Grapefruit juice may increase blood levels of quetiapine, increasing the effects and adverse effects of quetiapine.
Quetiapine is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit can inhibit CYP3A4. In one case report, a healthy 28-year-old female with bipolar disorder stabilized on quetiapine 800 mg daily presented with quetiapine toxicity considered to be related to consuming a gallon of grapefruit juice over the past 24 hours.

Likelihood Probable Evidence B
Quinidine

Grapefruit juice can alter blood levels of quinidine, potentially increasing or decreasing the clinical effects of quinidine.
Clinical research shows that grapefruit juice decreases quinidine absorption, clearance, and metabolism, and prolongs the half-life by about 20%.

Likelihood Probable Evidence B
Scopolamine (Transderm Scop)

Grapefruit juice can increase blood levels of scopolamine, potentially increasing the effects and adverse effects of scopolamine.
Clinical research shows that grapefruit juice can inhibit cytochrome P450 3A4 (CYP3A4) metabolism of scopolamine, increasing its absorption and plasma concentrations. Oral bioavailability of scopolamine can increase by 30% when administered with 150 mL of grapefruit juice.

Likelihood Probable Evidence B
Sildenafil (Viagra)

Grapefruit juice can increase blood levels of sildenafil, potentially increasing the effects and adverse effects of sildenafil.
Clinical research shows that grapefruit juice inhibits cytochrome P450 3A4 (CYP3A4) metabolism of sildenafil, increasing its absorption and plasma concentrations. Oral bioavailability of sildenafil can increase by 23% when administered with 500 mL of commercially available grapefruit juice.

Likelihood Probable Evidence B
Tacrolimus (Prograf)

Grapefruit juice can increase blood levels of tacrolimus, potentially increasing the effects and adverse effects of tacrolimus.
Clinical research shows that drinking grapefruit juice 200 mL daily while taking tacrolimus 3 mg daily increases the trough blood concentration of tacrolimus by approximately 3-fold in patients with connective tissue diseases. A single case has also reported a 10-fold increase in tacrolimus trough levels after the ingestion of grapefruit juice over 3 days. This effect is attributed to the inhibition of cytochrome P450 3A4 (CYP3A4) by grapefruit.

Likelihood Likely Evidence B
Terfenadine (Seldane)

Grapefruit juice can increase blood levels of terfenadine, potentially increasing the effects and adverse effects of terfenadine.
Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of terfenadine. The mechanism of action is unclear.

Likelihood Probable Evidence B
Ticagrelor (Brilinta)

Grapefruit juice can increase blood levels of ticagrelor, thereby increasing the effects and adverse effects of ticagrelor.
Ticagrelor is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit can inhibit CYP3A4. A small clinical study shows that taking grapefruit juice with ticagrelor increases blood levels of ticagrelor more than two-fold and increases the antiplatelet activity of ticagrelor. Additionally, animal research shows that grapefruit juice increases peak plasma concentration (Cmax) and the area under the drug concentration-time curve (AUC) of ticagrelor.

Likelihood Probable Evidence B
Aliskiren (Tekturna, Rasilez)

Grapefruit juice can decrease blood levels of aliskiren, potentially decreasing the clinical effects of aliskiren.
Clinical research shows that grapefruit juice can decrease aliskiren levels by approximately 60% by inhibiting organic anion transporting polypeptide (OATP). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction.

Likelihood Possible Evidence B
Budesonide (Entocort, Uceris)

Grapefruit juice can increase blood levels of budesonide, potentially increasing the effects and adverse effects of budesonide.
Budesonide is metabolized by cytochrome P450 3A4 (CYP3A4). A small clinical study shows that taking grapefruit juice along with oral budesonide increases the plasma concentration of budesonide. This effect is attributed to grapefruit-induced inhibition of CYP3A4 in both the colon and small intestine.

Likelihood Probable Evidence B
Caffeine

Grapefruit juice can decrease the clearance of caffeine, potentially increasing the effects and adverse effects of caffeine.
Clinical research shows that grapefruit juice decreases caffeine clearance.

Likelihood Probable Evidence D
Colchicine

Theoretically, grapefruit juice might increase blood levels of colchicine, potentially increasing the effects and adverse effects of colchicine.
Colchicine is an alkaloid that undergoes P-glycoprotein (P-gp) mediated drug efflux in the intestines, followed by metabolism by cytochrome P450 3A4 (CYP3A4). There is concern that grapefruit juice will increase the effects and adverse effects of colchicine due to grapefruit-induced inhibition of P-gp and/or CYP3A4. In vitro evidence shows that grapefruit juice increases absorption of colchicine by inhibiting P-gp. A case of acute colchicine toxicity has been reported for an 8-year-old female who drank grapefruit juice while taking high-dose colchicine, long-term. However, one small clinical study in healthy adults shows that drinking grapefruit juice 240 mL twice daily for 4 days does not affect the bioavailability or adverse effects of a single dose of colchicine 0.6 mg taken on the fourth day.

Likelihood Possible Evidence B
Cytochrome P450 1A2 (Cyp1A2) Substrates

Theoretically, grapefruit juice might increase levels of drugs metabolized by CYP1A2.
In vitro research suggests that grapefruit juice might inhibit CYP1A2 enzymes. So far, this interaction has not been reported in humans.

Likelihood Possible Evidence D
Cytochrome P450 2C19 (Cyp2C19) Substrates

Theoretically, grapefruit juice might increase levels of drugs metabolized by CYP2C19.
In vitro research suggests that grapefruit juice might inhibit CYP2C19 enzymes. Also, a small clinical study shows that taking grapefruit juice with clopidogrel, an antiplatelet prodrug that is metabolized primarily by CYP2C19, decreases plasma levels of the active metabolite and impairs the antiplatelet effect of clopidogrel. This effect is likely due to grapefruit-induced inhibition of CYP2C19.

Likelihood Possible Evidence B
Cytochrome P450 2C9 (Cyp2C9) Substrates

Theoretically, grapefruit juice might increase levels of drugs metabolized by CYP2C9.
In vitro research suggests that grapefruit juice might inhibit CYP2C9 enzymes. So far, this interaction has not been reported in humans.

Likelihood Possible Evidence D
Empagliflozin (Jardiance)

Theoretically, grapefruit juice may increase the levels and clinical effects of empagliflozin.
Animal research suggests grapefruit juice increases the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of empagliflozin, possibly due to inhibition of metabolism by uridine diphosphoglucuronosyl transferase (UGT). This effect has not been reported in humans.

Likelihood Possible Evidence D
Erythromycin

Grapefruit juice can increase blood levels of erythromycin, potentially increasing the effects and adverse effects of erythromycin.
Clinical research shows that concomitant use of erythromycin with grapefruit can inhibit cytochrome P450 3A4 (CYP3A4) metabolism of erythromycin, increasing plasma concentrations of erythromycin by 35%.

Likelihood Probable Evidence B
Fexofenadine (Allegra)

Grapefruit juice can decrease blood levels of fexofenadine, thereby decreasing the clinical effects of fexofenadine.
Clinical research shows that grapefruit juice can significantly decrease oral absorption and blood levels of fexofenadine. In one study, consuming a drink containing grapefruit juice 25% decreased bioavailability of fexofenadine by about 24%. Consuming a full-strength grapefruit juice drink reduced bioavailability by 67%. In another study, consuming grapefruit juice 300 mL decreased fexofenadine levels by 42%. Consuming 1200 mL of grapefruit juice reduced levels by 64%. Similarly, drinking grapefruit juice 240 mL decreased the oral bioavailability of fexofenadine by 25% in another pharmacokinetic study. Fexofenadine manufacturer data indicates that concomitant administration of grapefruit juice and fexofenadine results in larger wheal and flare sizes in research models. This suggests that grapefruit also reduces the clinical response to fexofenadine.
Grapefruit juice seems to inhibit organic anion transporting polypeptide (OATP), which is a drug transporter in the gut, liver, and kidney. Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction.

Likelihood Likely Evidence B
Fluvoxamine (Luvox)

Grapefruit juice can increase blood levels of fluvoxamine, potentially increasing the effects and adverse effects of fluvoxamine.
Clinical research shows that grapefruit juice inhibits metabolism and increases fluvoxamine levels and peak concentration.

Likelihood Possible Evidence B
Itraconazole (Sporanox)

Grapefruit juice can interfere with itraconazole absorption, although the clinical significance of this interaction is unclear.
Clinical research shows that grapefruit juice can affect itraconazole absorption and might increase or decrease itraconazole levels.

Likelihood Possible Evidence B
Levothyroxine (Synthroid, Others)

Grapefruit juice can decrease blood levels of levothyroxine, potentially decreasing the effectiveness of levothyroxine.
Clinical research shows that grapefruit juice modestly decreases levothyroxine levels by 11% by inhibiting organic anion transporting polypeptide (OATP). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction.

Likelihood Possible Evidence B
Losartan (Cozaar)

Grapefruit juice can decrease blood levels of the active metabolite of losartan, potentially decreasing the clinical effects of losartan.
Losartan is an inactive prodrug which must be metabolized to its active form, E-3174, to be effective. In one human study, grapefruit juice reduced losartan metabolism, increased losartan AUC, and reduced the AUC of the major active losartan metabolite, E-3174.

Likelihood Probable Evidence B
Nadolol (Corgard)

Grapefruit juice might decrease blood levels of nadolol, potentially decreasing the clinical effects of nadolol.
Nadolol is a substrate of organic anion transporting polypeptide 1A2 (OATP1A2). Some research shows that grapefruit juice and its constituent naringin can inhibit organic anion transporting polypeptides (OATP), which can reduce the bioavailability of OATP substrates. However, preliminary clinical research shows that grapefruit juice containing a low amount of naringin does not significantly affect levels of nadolol. It is not known if grapefruit juice containing higher amounts of naringin reduces the bioavailability of nadolol.

Likelihood Possible Evidence B
Nilotinib (Tasigna)

Grapefruit juice can increase blood levels of nilotinib, potentially increasing the effects and adverse effects of nilotinib.
Clinical research shows that grapefruit juice inhibits metabolism and increases absorption of nilotinib. Grapefruit juice increases nilotinib levels by 29% and peak concentration by 60%.

Likelihood Probable Evidence B
Oxycodone (Oxycontin)

Grapefruit juice can increase blood levels of oxycodone, potentially increasing the effects and adverse effects of oxycodone.
Oxycodone is metabolized by both cytochrome P450 3A4 (CYP3A4) and cytochrome P450 2D6 (CYP2D6). A small clinical study shows that grapefruit juice can increase plasma levels of oral oxycodone about 1.7-fold by inhibiting CYP3A4. While the analgesic effects of oxycodone do not seem to be affected, taking grapefruit juice along with oxycodone may theoretically increase the adverse effects of oxycodone.

Likelihood Probable Evidence B
Pitavastatin (Livalo)

Grapefruit juice can increase blood levels of pitavastatin, potentially increasing the effects and adverse effects of pitavastatin.
Pharmacokinetic research shows that taking grapefruit juice with pitavastatin 2-4 mg can increase blood levels of pitavastatin by 13% to 14%. Unlike simvastatin and atorvastatin, pitavastatin is not significantly metabolized by cytochrome P450 3A4 (CYP3A4) enzymes. Grapefruit juice appears to increase levels of pitavastatin by inhibiting its uptake by organic anion transporting polypeptide 1B1 (OATP1B1) into hepatocytes for metabolism and clearance from the body. Grapefruit juice seems to increase levels of pitavastatin to a greater degree in patients homozygous for a specific polymorphism (388A>G) in the OATP1B1 gene compared to those heterozygous for this polymorphism.

Likelihood Likely Evidence B
Prasugrel (Effient)

Grapefruit juice can decrease blood levels of the active metabolite of prasugrel, thereby decreasing the antiplatelet effect of prasugrel.
Prasugrel is a prodrug that is metabolized by cytochrome P450 3A4 (CYP3A4) into its active metabolite. A small pharmacokinetic study in healthy volunteers shows that drinking grapefruit juice 200 mL three times daily for 4 days and taking a single dose of prasugrel 10 mg with an additional 200 mL of grapefruit juice on day 3, results in a 49% lower peak plasma level and a 26% lower overall plasma exposure to the active metabolite when compared with drinking water. However, despite the reduced exposure, platelet aggregation seems to be reduced by an average of only 5%. The clinical significance of this interaction is unclear.

Likelihood Probable Evidence B
Primaquine

Grapefruit juice may increase blood levels of primaquine, potentially increasing the effects and adverse effects of primaquine.
Clinical research shows that grapefruit juice increases the bioavailability of primaquine by approximately 20%. The clinical significance of this interaction is not clear.

Likelihood Possible Evidence B
Rivaroxaban (Xarelto)

Theoretically, grapefruit juice may increase the concentration and clinical effects of rivaroxaban.
Rivaroxaban is metabolized partially by cytochrome P450 3A4 (CYP3A4). Grapefruit juice can inhibit CYP3A4. Animal research shows that grapefruit juice increases the peak plasma concentration (Cmax) of rivaroxaban by about four-fold, without increasing the area under the drug concentration-time curve (AUC).

Likelihood Possible Evidence D
Saquinavir (Fortovase, Invirase)

Grapefruit juice can increase blood levels of saquinavir, potentially increasing the effects and adverse effects of saquinavir.
Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of saquinavir.

Likelihood Probable Evidence B
Sertraline (Zoloft)

Grapefruit juice can increase blood levels of sertraline, potentially increasing the effects and adverse effects of sertraline.
Clinical research shows that grapefruit juice inhibits the cytochrome P450 3A4 (CYP3A4) metabolism of sertraline, increasing blood levels of sertraline.

Likelihood Possible Evidence B
Sunitinib (Sutent)

Grapefruit juice may slightly increase blood levels of sunitinib, potentially increasing the effects and adverse effects of sunitinib.
Sunitinib is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit and grapefruit juice can inhibit CYP3A4 and increase levels of some drugs metabolized by this enzyme. One small clinical study shows that drinking 200 mL of grapefruit juice three times daily can increase the bioavailability of sunitinib by 11% . While this effect is unlikely to be clinically significant, patients should use caution when using grapefruit along with sunitinib. Dose adjustments may be necessary.

Likelihood Unlikely Evidence B
Tadalafil (Cialis)

Theoretically, grapefruit juice might increase blood levels of tadalafil, potentially increasing the effects and adverse effects of tadalafil.
Animal research shows that grapefruit juice increases tadalafil serum concentrations and overall exposure, likely through inhibition of cytochrome P450 3A4 enzymes.

Likelihood Possible Evidence D
Talinolol

Grapefruit juice might decrease blood levels of talinolol, potentially decreasing the clinical effects of talinolol.
Clinical research suggests that grapefruit juice reduces talinolol bioavailability, likely by inhibiting intestinal uptake. The clinical significance of this effect is unclear.

Likelihood Possible Evidence B
Theophylline

Grapefruit juice can decrease blood levels of theophylline, potentially decreasing the effectiveness of theophylline.
Clinical research shows that grapefruit juice seems to modestly decrease theophylline levels when given concurrently with sustained-release theophylline. The mechanism of this interaction is unknown.

Likelihood Probable Evidence B
Tolvaptan (Samsca)

Grapefruit juice can increase blood levels of tolvaptan, potentially increasing the effects and adverse effects of tolvaptan.
Tolvaptan is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit can inhibit CYP3A4. A small clinical study shows that grapefruit juice can increase the bioavailability and blood levels of tolvaptan by approximately 1.6-fold for up to 16 hours.

Likelihood Probable Evidence B
Warfarin (Coumadin)

Theoretically, drinking large amounts of grapefruit juice might increase the effects and adverse effects of warfarin.
In one case report, a patient experienced significantly increased international normalized ratio (INR) associated with consumption of 50 ounces of grapefruit juice daily. However, smaller amounts of grapefruit juice might not be a problem. In a small clinical trial, consumption of 24 ounces of grapefruit juice daily for one week had no effect on INR in males treated with warfarin.

Likelihood Possible Evidence D
Acebutolol (Sectral)

Grapefruit juice can decrease blood levels of acebutolol, potentially decreasing the clinical effects of acebutolol.
Clinical research shows that grapefruit juice can modestly decrease acebutolol levels by 7% and reduce peak plasma concentration by 19% by inhibiting organic anion transporting polypeptide (OATP). The acebutolol half-life is also extended by 1.1 hours when grapefruit juice is consumed concomitantly. Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction.

Likelihood Possible Evidence B
Amprenavir (Agenerase)

Grapefruit juice might decrease blood levels of amprenavir, although this is not likely to be clinically significant.
Some clinical research shows that grapefruit juice can slightly decrease amprenavir levels; however, this is probably not clinically significant.

Likelihood Possible Evidence B
P-Glycoprotein Substrates

Grapefruit juice does not seem to affect renal P-glycoprotein (P-gp). Theoretically, it might inhibit intestinal P-gp, but evidence is conflicting.
While most in vitro research shows that grapefruit products inhibit P-gp,, research in humans is less clear. Two small clinical studies in healthy adults using digoxin as a probe substrate show that grapefruit juice does not inhibit P-gp in the kidneys. It is unclear whether this applies to intestinal P-gp, for which digoxin is not considered to be a sensitive probe. Grapefruit juice has been shown to reduce levels of fexofenadine, and increase levels of quinidine. However, as both of these drugs are also substrates of other enzymes and transporters, it is unclear what role, if any, intestinal P-gp has in these findings.

Likelihood Possible Evidence B
Monograph

Grapefruit: Uses, Safety & Side Effects

Medically reviewed by · Reviewed July 2026 ·
The bottom line

Grapefruit is a nutritious citrus fruit rich in vitamin C and other nutrients, and it is generally safe to eat. However, grapefruit is famous for serious interactions with many prescription medicines, so anyone taking medication should check with a pharmacist or doctor before consuming it regularly.

Grapefruit
Scientific name
Citrus paradisi
Family
Rutaceae
Part used
Fruit, juice, peel, and seed extract
Common forms
Fresh fruit, juice, seed extract (capsules or liquid), essential oil
People commonly use it for
  • Source of vitamin C
  • Digestive complaints
  • Antimicrobial (seed extract)
  • Weight management
  • Skin and cosmetic uses

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance
OverallUse caution

The fruit is safe to eat for most people, but it interacts with many medicines.

PregnancyInsufficient reliable information

There is insufficient reliable information available about the safety of using medicinal amounts of grapefruit during pregnancy and lactation; avoid u...

Read the full pregnancy detail
BreastfeedingInsufficient reliable information

There is insufficient reliable information available about the safety of using medicinal amounts of grapefruit during pregnancy and lactation; avoid u...

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Grapefruit is a tropical and subtropical citrus fruit known for its tart, tangy, and slightly bitter flavor. It grows on evergreen trees and is widely cultivated in warm regions, including parts of the United States, the Caribbean, and other warm climates around the world.

There are several varieties, including white, pink, and red grapefruit. The color differences mostly come from natural pigments such as lycopene and beta-carotene. Pink and red grapefruits tend to be sweeter, while white grapefruit is more bitter.

People eat grapefruit fresh or drink the juice, and it is a good source of vitamin C, vitamin A, potassium, and fiber. Grapefruit and grapefruit seed extract are also sold as dietary supplements for a range of uses, from digestion to fighting germs.

How it works

Grapefruit contains vitamin C, fiber, potassium, and antioxidant plant compounds such as flavonoids (for example, naringin and naringenin) and lycopene in the pink and red varieties. These compounds are studied for their antioxidant activity, mostly in laboratory settings.

Grapefruit seed extract contains plant compounds that may slow the growth of certain bacteria and fungi in test-tube studies. However, the real-world effect in the body is not well proven.

Importantly, grapefruit also contains compounds called furanocoumarins. These block an enzyme in the gut that normally breaks down many medicines. This is the main reason grapefruit can cause major drug interactions, which are covered separately on this page.

Effectiveness

Does Grapefruit work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by .

Evidence overview · 17 uses evaluated
17 Insufficient evidence
How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.
2Likely EffectiveGood evidence, though not yet conclusive.
3Possibly EffectiveSome evidence suggests a benefit.
4Possibly IneffectiveSome evidence it may not help.
5Likely IneffectiveFairly strong evidence it doesn’t help.
6IneffectiveStrong evidence it doesn’t work.
7Insufficient Reliable Evidence to RateToo little research to say either way.

For Grapefruit, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 17 conditions — evidence insufficient to rate
Insufficient Reliable Evidence To Rate Acne
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using topical grapefruit oil for acne, there is insufficient reliable information about the clinical effects of grapefruit for this purpose.

Insufficient Reliable Evidence To Rate Asthma
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral grapefruit is beneficial in patients with asthma.

Insufficient Reliable Evidence To Rate Atherosclerosis
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral grapefruit to treat or prevent atherosclerosis, there is insufficient reliable information about the clinical effects of grapefruit for this purpose.

Insufficient Reliable Evidence To Rate Atopic dermatitis (eczema)
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral grapefruit seed extract is beneficial in patients with atopic dermatitis.

Insufficient Reliable Evidence To Rate Depression
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using inhaled grapefruit oil as aromatherapy for depression, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.

Insufficient Reliable Evidence To Rate Gingivitis
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using topical grapefruit oil as a rinse for gingivitis, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.

Insufficient Reliable Evidence To Rate Headache
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using inhaled grapefruit oil as aromatherapy for headache, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.

Insufficient Reliable Evidence To Rate Hypercholesterolemia
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral grapefruit is beneficial in patients with hypercholesterolemia.

Insufficient Reliable Evidence To Rate Hypertriglyceridemia
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral grapefruit is beneficial in patients with hypertriglyceridemia.

Insufficient Reliable Evidence To Rate Intestinal parasite infection
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral grapefruit seed extract for intestinal parasite infections, there is insufficient reliable information about the clinical effects of grapefruit for this purpose.

Insufficient Reliable Evidence To Rate Lice
Rating & evidence shown verbatim from Natural Medicines

It is unclear if topical grapefruit extract is beneficial in children with head lice.

Insufficient Reliable Evidence To Rate Obesity
Rating & evidence shown verbatim from Natural Medicines

While some small studies suggest that oral grapefruit extract, taken in combination with other citrus extracts, may modestly improve weight loss, the effect of oral grapefruit alone is unclear.

Insufficient Reliable Evidence To Rate Pharyngitis
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using topical grapefruit oil as a gargle for pharyngitis, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.

Insufficient Reliable Evidence To Rate Psoriasis
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral grapefruit for psoriasis, there is insufficient reliable information about the clinical effects of grapefruit for this purpose.

Insufficient Reliable Evidence To Rate Stress
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using inhaled grapefruit oil as aromatherapy for stress, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.

Insufficient Reliable Evidence To Rate Upper respiratory tract infection (URTI)
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using grapefruit oil as aromatherapy for various upper respiratory tract infections, including influenza and the common cold, there is insufficient reliable information about the clinical effects of grapefruit oil for these conditions.

Insufficient Reliable Evidence To Rate Vaginal candidiasis
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral and topical grapefruit seed extract for vaginal candidiasis, there is insufficient reliable information about the clinical effects of grapefruit seed extract for this purpose.

Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.

Safety & precautions

For most people, eating grapefruit or drinking its juice is safe and nutritious. The biggest concern is not the fruit itself but its well-known interactions with many prescription and over-the-counter medicines.

Who should be cautious: Anyone taking regular medication should talk with a pharmacist or doctor before adding grapefruit or grapefruit supplements to their diet. People with certain conditions affected by potassium should also check with their provider.

Pregnancy: Eating grapefruit as a normal food is generally considered fine, but concentrated supplements and grapefruit seed extract have not been well studied in pregnancy and are best avoided unless your doctor approves.

Breastfeeding: Grapefruit as a food is generally acceptable, but the safety of concentrated extracts while breastfeeding is not well established, so caution is advised.

Side effects

Eating grapefruit is usually well tolerated. Some people may experience mild stomach upset, heartburn, or a sour reaction because of its acidity.

The peel and essential oil can irritate the skin in some people. Grapefruit seed extract products are sometimes very concentrated and may cause irritation if not properly diluted.

The most serious risk does not come from grapefruit itself but from how it changes the way the body handles certain medicines. This can raise drug levels in the blood and lead to harmful effects, which is why checking with a healthcare professional is so important.

Grapefruit: Reported Adverse Effects

Documented safety reports on Grapefruit from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

Orally, grapefruit and grapefruit juice are generally well tolerated.

Serious Adverse Effects (Rare):

Orally: Allergic reactions in sensitive individuals have been reported. When large quantities are consumed, arrhythmias, mineralocorticoid excess, QT prolongation, and pseudohyperaldosteronism have been reported. There is also some concern for increased breast cancer risk with grapefruit consumption.

Reports by condition
Arrhythmia Cardiovascular

Orally, consumption of pink grapefruit juice 1000 mL can cause QT prolongation and cause arrhythmias in healthy patients and worsen arrhythmias in cardiomyopathy patients.

  1. Zitron E, Scholz E, Owen RW, et al. QTc prolongation by grapefruit juice and its potential pharmacological basis: HERG channel blockade by flavonoids. Circulation 2005;835:835-8.
  2. Piccirillo G, Magrì D, Matera S, Magnanti M, Pasquazzi E, Schifano E, Velitti S, Mitra M, Marigliano V, Paroli M, Ghiselli A. Effects of pink grapefruit juice on QT variability in patients with dilated or hypertensive cardiomyopathy and in healthy subject
Breast cancer Oncologic

Preliminary population research shows that postmenopausal adults who consume a quarter or more of a whole grapefruit daily have a 25% to 30% increased risk of developing breast cancer. Grapefruit is a potent inhibitor of cytochrome P450 3A4, which metabolizes estrogen. Consuming large amounts of grapefruit might significantly increase endogenous estrogen levels and therefore increase the risk of breast cancer. More evidence is needed to validate these findings. Until more is known, advise patients to consume grapefruit in moderation.

  1. Monroe KR, Murphy SP, Kolonel LN, Pike MC. Prospective study of grapefruit intake and risk of breast cancer in postmenopausal women: the Mutliethnic Cohort Study. Br J Cancer 2007;97:440-5.
Kidney stones (nephrolithiasis) Renal

In population research, consumption of 240 mL/day of grapefruit juice is associated with an increased risk of kidney stones.

  1. Curhan GC, Willett WC, Speizer FE, Stamfer MJ. Beverage use and risk of kidney stones in women. Ann Intern Med 1998;128:534-40.
  2. Curhan, G. C., Willett, W. C., Rimm, E. B., Spiegelman, D., and Stampfer, M. J. Prospective study of beverage use and the risk of kidney stones. Am J Epidemiol. 2-1-1996;143(3):240-247.
Pruritus Immunologic

Orally, grapefruit can cause allergic sensitization characterized by eosinophilic gastroenteritis, urticaria, and generalized pruritus.

  1. Kumar, A., Teuber, S. S., Naguwa, S., Prindiville, T., and Gershwin, M. E. Eosinophilic gastroenteritis and citrus-induced urticaria. Clin Rev Allergy Immunol 2006;30(1):61-70.
  2. Ferdman, R. M., Ong, P. Y., and Church, J. A. Pectin anaphylaxis and possible association with cashew allergy. Ann.Allergy Asthma Immunol. 2006;97(6):759-760.
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

Dosing

There is no official standardized dose for grapefruit as a supplement. Grapefruit is most often simply eaten as a fruit or consumed as juice as part of a normal diet.

For grapefruit seed extract and other concentrated products, there is no well-established effective or safe dose. If you choose to use a product, follow the directions on the label and start conservatively.

Because grapefruit can interact strongly with medicines, always check with a pharmacist or doctor before using grapefruit products regularly, especially in supplement form.

Pregnancy & Breastfeeding

Grapefruit & Pregnancy

Insufficient reliable information

There is insufficient reliable information available about the safety of using medicinal amounts of grapefruit during pregnancy and lactation; avoid using.

Grapefruit & Breastfeeding

Insufficient reliable information

There is insufficient reliable information available about the safety of using medicinal amounts of grapefruit during pregnancy and lactation; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

© 2026 Therapeutic Research Center

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

The 157 references that drive our Grapefruit monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Penzak SR, Gubbins PO, Gurley BJ, et al. Grapefruit juice decreases the systemic availability of itraconazole capsules in healthy volunteers. Ther Drug Monit 1999;21:304-9. PubMed
  2. Ioannides-Demos LL, Christophidis N, et al. Dosing implications of a clinical interaction between grapefruit juice and cyclosporine and metabolite concentrations in patients with autoimmune diseases. J Rheumatol 1997;24:49-54.
  3. Josefsson M, Zackrisson AL, Ahlner J. Effect of grapefruit juice on the pharmacokinetics of amlodipine in healthy volunteers. Eur J Clin Pharmacol 1996;51:189-93. PubMed
  4. Garg SK, Kumar N, Bhargava VK, Prabhakar SK. Effect of grapefruit juice on carbamazepine bioavailability in patients with epilepsy. Clin Pharmacol Ther 1998;64:286-8. PubMed
  5. Weber A, Jager R, Borner A, et al. Can grapefruit juice influence ethinylestradiol bioavailability? Contraception 1996;53:41-7.
  6. Schubert W, Cullberg G, Edgar B, Hedner T. Inhibition of 17 beta-estradiol metabolism by grapefruit juice in ovariectomized women. Maturitas 1994;20:155-63.
  7. Kantola T, Kivisto KT, Neuvonen PJ, et al. Grapefruit juice greatly increases serum concentrations of lovastatin and lovastatin acid. Clin Pharmacol Ther 1998 63:397-402. PubMed
  8. Bailey DG, Spence JD, Munoz C, Arnold JM. Interaction of citrus juices with felodipine and nifedipine. Lancet 1991;337:268-9. PubMed
  9. Bailey DG, Arnold JM, Strong HA, et al. Effect of grapefruit juice and naringin on nisoldipine pharmacokinetics. Clin Pharmacol Ther 1993;54:589-94. PubMed
  10. Rau SE, Bend JR, Arnold MO, et al. Grapefruit juice-terfenadine single-dose interaction: magnitude, mechanism, and relevance. Clin Pharmacol Ther 1997 61:401-9. PubMed
  11. Offman EM, Freeman DJ, Dresser GK, et al. Cisapride interaction with grapefruit juice and red wine. Clin Pharmacol Ther 2000;67:110 (abstract PI-83).
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  13. Soldner A, Christians U, Susanto M, et al. Grapefruit juice activates P-glycoprotein-mediated drug transport. Pharm Res 1999;16:478-85. PubMed
  14. Zaidenstein R, Avni B, Dishi V, et al. Effect of grapefruit juice on the pharmacokinetics of losartan in healthy volunteers. Clin Pharmacol Ther 1998;65:(abstract PI-60). DOI
  15. Dresser GK, Bailey DG, Carruthers SG. Grapefruit juice-felodipine interaction in healthy seniors. Clin Pharmacol Ther 1998;65:(abstract PIII-63).
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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Brand directory

Brands that make products with Grapefruit

395 brands in our database make a supplement containing Grapefruit.

Product directory

Supplement products with Grapefruit

1,261 products in our database contain Grapefruit. Open any to see its full ingredient list and every drug interaction we check.

Super Bio Vegetarian by Priority One Nutritional Supplements Tablet Or Pill 90 Tablet(s) Off market View ingredients & interactions Super Bio Vegetarian by Priority One Nutritional Supplements Tablet Or Pill 90 Tablet(s) Off market View ingredients & interactions Super Bio Vegetarian by Priority One Nutritional Supplements Tablet Or Pill 180 Tablet(s) Off market View ingredients & interactions Super Greens by Nature's Bounty Powder 9.62 oz. · 273 g Off market View ingredients & interactions Super Hi-Potency Multi-Vitamin & Mineral With Phyto-Nutrients by Windmill Tablet Or Pill 60 Tablet(s) Off market View ingredients & interactions Super Hi-Potency Multi-Vitamin & Mineral With Phytonutrients by Windmill Tablet Or Pill 60 Tablet(s) Off market View ingredients & interactions Super Juice by Windmill Health Products Other (e.g. Tea Bag) 60 Caplet(s) Off market View ingredients & interactions Super Lean 450 by Extreme Products Capsule 60 Capsule(s) Off market View ingredients & interactions Super Ox by Wholly Liquid Liquid 15.2 Fluid Ounce(s) · 450 mL Off market View ingredients & interactions Super Reds Berry Flavor by Country Farms Powder 7.1 Oz(s) · 200 Gram(s) Off market View ingredients & interactions Super Reds Mixed Berry Flavor by Country Farms Powder 7.1 Oz(s) · 200 Gram(s) Off market View ingredients & interactions Superfood Multivitamin by APSU Tablet Or Pill Off market View ingredients & interactions SynerPro Calcium-Magnesium With SynerPro Concentrate by Nature's Sunshine Tablet Or Pill 150 Tablet(s) Off market View ingredients & interactions Thermo Detonator by Grenade Capsule Off market View ingredients & interactions Time Fighters for Men by Physician's Signature Other (e.g. Tea Bag) 120 Caplet(s) Off market View ingredients & interactions Total Cleanse Liver by Solaray Capsule 60 Vegetable Capsule(s) Off market View ingredients & interactions Triple Shredder Body-Shaper by Irwin Naturals Softgel Capsule 60 Liquid Softgel(s) Off market View ingredients & interactions Ultimate-X Vitamin Pak by Xcel Sports Nutrition Unknown 325 Gram(s) Off market View ingredients & interactions Ultra B-12 by NOW Liquid 4 fl. Oz. · 118 mL Off market View ingredients & interactions Ultra B-12 by NOW Liquid 16 fl. Oz. · 473 mL Off market View ingredients & interactions Ultra B-12 by NOW Liquid 4 fl. Oz. · 118 mL Off market View ingredients & interactions Ultra B-12 by NOW Liquid 16 fl. Oz. · 473 mL Off market View ingredients & interactions Ultra B-12 by NOW Liquid 4 fl. Oz. · 118 mL Off market View ingredients & interactions Ultra B-12 by NOW Liquid 16 fl. Oz. · 473 mL Off market View ingredients & interactions
Pharmacist Counseling Corner

Grapefruit: Common Questions

What is Grapefruit used for, and does it work?
People use Grapefruit for a range of reasons, but according to the Natural Medicines database the current clinical evidence is insufficient to confirm it works for the specific conditions it has been studied for. See the graded list on this page, and talk to your pharmacist or doctor before relying on it for any condition.
Does Grapefruit interact with prescription medications?
Yes. We list 990 medications with a known interaction with Grapefruit, including 776 rated major. Use the checker above to see how Grapefruit interacts with a specific drug.
How are Grapefruit interactions rated?
Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.
Is it safe to take Grapefruit with my medications?
It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.
Where does this Grapefruit interaction information come from?
Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.
Is Grapefruit good for me?
Grapefruit is a nutritious fruit that provides vitamin C, fiber, and potassium, and it can be a healthy part of a balanced diet for most people who are not taking interacting medicines.
Does Grapefruit help with weight loss?
Some small studies have explored Grapefruit and weight, but the results are mixed and not strong. Grapefruit can be a low-calorie, filling food, but it is not a proven weight-loss treatment.
Is Grapefruit seed extract proven to fight infections?
Most evidence for Grapefruit seed extract comes from laboratory studies, and some products contain added preservatives. There is not enough good human research to confirm it treats infections.
Can I eat Grapefruit while pregnant?
Eating Grapefruit as a normal food is generally considered fine during pregnancy, but concentrated supplements or seed extract are best avoided unless your doctor approves.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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Products that contain Grapefruit

A rotating sample of real supplements in our database that list Grapefruit — open any to see its full ingredients and every drug interaction we check.

See all 1,261 products with Grapefruit →
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