Herb & supplement monograph

Black Pepper Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

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

But these pages have grown well beyond that into a full monograph — what Black Pepper 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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Black Pepper Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Black Pepper drug interaction appears low for most people, although a small group of medications deserves genuine attention. None of the listed interactions are rated major, and most rest on lab or animal research rather than effects actually shown in people.

Interactions deserving the most attention

The best-documented concern is phenytoin, where human research found black pepper's piperine can roughly double blood levels of this seizure medicine, which has a narrow safety margin. A clinical study also showed piperine raises levels of carbamazepine, another seizure drug, and black pepper's diuretic effect may raise levels of lithium, which may need a dose change. Human studies also show higher levels of propranolol, rifampin, theophylline, and nevirapine, though the nevirapine study saw no harm. People on diabetes medications should watch for low blood sugar, since animal research suggests black pepper can lower glucose.

What the rest of the list means

The long list mostly reflects theory, not proven harm. Black pepper may affect enzymes and transporters the body uses to process many medications, so hundreds of drugs get flagged automatically. For most of these, the predicted effect has never been reported in people.

Check your medications against Black Pepper

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

Interaction report

Drugs that interact with Black Pepper

1020 medications have a known interaction with Black Pepper, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Black Pepper using our pharmacist-reviewed interaction data.

AI summaries are generated from our Black Pepper interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

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 Black Pepper 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 Black Pepper affects

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

All 17 drug categories Black Pepper interacts with

Anticoagulant/antiplatelet DrugsAntidiabetes DrugsAtorvastatin (lipitor)Cyclosporine (neoral, Sandimmune)Cytochrome P450 2d6 (cyp2d6) SubstratesCytochrome P450 3a4 (cyp3a4) SubstratesLithiumNevirapine (viramune)P-glycoprotein SubstratesPentobarbital (nembutal)Phenytoin (dilantin)Propranolol (inderal)Rifampin (rifadin)TheophyllineAmoxicillin (amoxil, Trimox)Carbamazepine (tegretol)Cytochrome P450 1a2 (cyp1a2) Substrates

Anticoagulant/Antiplatelet Drugs

Theoretically, black pepper might increase the risk of bleeding when taken with antiplatelet or anticoagulant drugs.
In vitro research shows that piperine, a constituent of black pepper, seems to inhibit platelet aggregation. This has not been reported in humans.

Likelihood Possible Evidence D

Antidiabetes Drugs

Theoretically, black pepper might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Animal research shows that piperine, a constituent of black pepper, can reduce blood glucose levels. Monitor blood glucose levels closely. Dose adjustments might be necessary.

Likelihood Possible Evidence D

Atorvastatin (Lipitor)

Theoretically, black pepper might increase blood levels of atorvastatin.
Animal research shows that taking piperine, a constituent of black pepper, 35 mg/kg can increase the maximum serum concentration of atorvastatin three-fold. This has not been reported in humans.

Likelihood Possible Evidence D

Cyclosporine (Neoral, Sandimmune)

Theoretically, black pepper might increase the effects and side effects of cyclosporine.
In vitro research shows that piperine, a constituent of black pepper, increases the bioavailability of cyclosporine. This has not been reported in humans.

Likelihood Possible Evidence D

Cytochrome P450 2D6 (Cyp2D6) Substrates

Theoretically, black pepper might increase levels of drugs metabolized by CYP2D6.
In vitro research suggests that some constituents of black pepper inhibit CYP2D6. This has not been reported in humans.

Likelihood Possible Evidence D

Cytochrome P450 3A4 (Cyp3A4) Substrates

Theoretically, black pepper might increase levels of drugs metabolized by CYP3A4.
In vitro research and pharmacokinetic simulation data suggest that piperine, a constituent of black pepper, as well as the pepper fruit seem to inhibit CYP3A4. This has not been reported in humans.

Likelihood Possible Evidence D

Lithium

Theoretically, black pepper might increase blood levels of lithium due to its diuretic effects. The dose of lithium might need to be reduced.
Black pepper is thought to have diuretic properties.

Likelihood Probable Evidence D

Nevirapine (Viramune)

Black pepper might increase blood levels of nevirapine.
Clinical research shows that piperine, a constituent of black pepper, increases the plasma concentration of nevirapine. However, no adverse effects were observed in this study.

Likelihood Probable Evidence D

P-Glycoprotein Substrates

Theoretically, black pepper might increase levels of P-glycoprotein substrates.
In vitro research shows that piperine, a constituent of black pepper, seems to inhibit P-glycoprotein.

Likelihood Possible Evidence D

Pentobarbital (Nembutal)

Theoretically, black pepper might increase the sedative effects of pentobarbital.
Animal research shows that piperine, a constituent of black pepper, increases pentobarbital-induced sleeping time.

Likelihood Possible Evidence D

Phenytoin (Dilantin)

Black pepper might increase blood levels of phenytoin.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption, slow elimination, and increase levels of phenytoin. Taking a single dose of black pepper 1 gram along with phenytoin seems to double the serum concentration of phenytoin. Consuming a soup with black pepper providing piperine 44 mg/200 mL of soup along with phenytoin also seems to increase phenytoin levels when compared with consuming the same soup without black pepper.

Likelihood Possible Evidence B

Propranolol (Inderal)

Black pepper might increase blood levels of propranolol.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and slow elimination of propranolol.

Likelihood Possible Evidence B

Rifampin (Rifadin)

Black pepper might increase blood levels of rifampin.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and serum levels of rifampin.

Likelihood Possible Evidence B

Theophylline

Black pepper might increase blood levels of theophylline.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and slow elimination of theophylline.

Likelihood Possible Evidence D

Amoxicillin (Amoxil, Trimox)

Theoretically, black pepper might increase the effects and side effects of amoxicillin.
Animal research shows that taking piperine, a constituent of black pepper, with amoxicillin increases plasma levels of amoxicillin. This has not been reported in humans.

Likelihood Possible Evidence D

Carbamazepine (Tegretol)

Theoretically, black pepper might increase blood levels of carbamazepine, potentially increasing the effects and side effects of carbamazepine.
One clinical study in patients taking carbamazepine 300 mg or 500 mg twice daily shows that taking a single 20 mg dose of purified piperine, a constituent of black pepper, increases carbamazepine levels. Piperine may increase carbamazepine absorption by increasing blood flow to the GI tract, increasing the surface area of the small intestine, or inhibiting cytochrome P450 3A4 (CYP3A4) in the gut wall. Absorption was significantly increased by 7-10 mcg/mL/hour. The time to eliminate carbamazepine was also increased by 4-8 hours. Although carbamazepine levels were increased, this did not appear to increase side effects. In vitro research also shows that piperine can increase carbamazepine levels by 11% in a time-dependent manner.

Likelihood Possible Evidence B

Cytochrome P450 1A2 (Cyp1A2) Substrates

Theoretically, black pepper might decrease levels and clinical effects of drugs metabolized by CYP1A2.
In vitro research suggests that black pepper induces CYP1A2. This has not been reported in humans.

Likelihood Possible Evidence D

Monograph

Black Pepper: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Black pepper is a common kitchen spice that is generally safe in the amounts used in food. Its extract, piperine, is mostly added to supplements to help the body absorb other ingredients (like curcumin from turmeric). Strong human evidence for black pepper treating specific health conditions is limited, so use supplement-strength products with care and check with your pharmacist.

Scientific name: Piper nigrum
Family: Piperaceae
Part used: Dried fruit (peppercorn) and its extract piperine
Common forms: Whole or ground spice, capsules, standardized piperine extracts (often labeled BioPerine), essential oil

People commonly use it for

Flavoring and culinary use
Digestive complaints like bloating and indigestion
Boosting absorption of other supplements
Antioxidant and anti-inflammatory support
Cold and congestion remedies

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

Safety at a glance

OverallLikely safe

Generally safe as a food spice; concentrated supplements should be used more cautiously.

PregnancyLikely Safe

When used orally in amounts commonly found in foods.

Read the full pregnancy detail

BreastfeedingLikely Safe

When used orally in amounts commonly found in foods. There is insufficient reliable information available about the safety of black pepper when used i...

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

Black pepper comes from the dried, unripe fruit (peppercorn) of the Piper nigrum plant, a flowering vine native to the southwestern coast of India. It is now grown across many tropical regions and is one of the most widely traded spices in the world.

Beyond the kitchen, black pepper has a long history in traditional systems such as Ayurveda, where it is used for digestion, coughs, and colds. Today it also appears in dietary supplements, usually as a concentrated extract called piperine, the compound that gives pepper its sharp bite.

How it works

The main active compound in black pepper is piperine, an alkaloid that creates its pungent flavor. Piperine appears to affect enzymes and transport proteins in the gut and liver that normally break down or remove substances from the body. By slowing these processes, it can let more of certain compounds stay in the bloodstream.

Black pepper also contains antioxidant plant compounds that may help neutralize unstable molecules called free radicals, and laboratory studies suggest possible anti-inflammatory effects. Keep in mind that most of this evidence comes from test-tube and animal research, and results in people may differ.

Effectiveness

Does Black Pepper work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 21 uses evaluated

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

Also studied for 21 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate Allergic rhinitis (hay fever)