Drug & supplement interaction

Sweet Orange + Fexofenadine

Fexofenadine brand name: Allegra.

Major Interaction
Medically reviewed by · Updated September 2026
The bottom line Major

Fexofenadine falls into 3 drug categories that Sweet Orange can interact with; the most serious is rated major. Consuming sweet orange juice can decrease oral absorption of OATP substrates.

Read the full interaction report
SeverityMajor
LikelihoodLikely
Interactions3
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Sweet Orange and Fexofenadine

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Sweet Orange interacts with whole categories of medication. Fexofenadine falls into 3 of those categories, so it can interact with Sweet Orange in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Major).

Major

ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP)

1 of 3

Why this applies to Fexofenadine

Fexofenadine falls under ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP) — the group Sweet Orange interacts with.

Consuming sweet orange juice can decrease oral absorption of OATP substrates. Separate administration by at least 4 hours.
Clinical research shows that consuming sweet orange juice inhibits OATP, which reduces bioavailability of oral drugs that are substrates of OATP. For example, sweet orange juice decreases bioavailability of fexofenadine, a substrate of OATP, by about 72% and of celiprolol, another OATP substrate, by up to 90%. Since sweet orange juice seems to affect OATP for a short time, recommend separating drug administration and consumption of sweet orange juice by at least 4 hours.
Severity Major Likelihood Likely Evidence B

Well-controlled human studies have demonstrated the likely existence of this interaction.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's something that surprises a lot of people: orange juice can actually make your Allegra (fexofenadine) work less well. Fexofenadine isn't broken down by the liver much. Instead, it relies on little 'doorways' in your gut called OATP transporters to get absorbed. Sweet orange juice temporarily blocks those doorways, so less of the drug gets into your bloodstream. In one study, orange juice cut fexofenadine absorption by about 72 percent.

What that means for you: your allergy relief may fall short, leaving you with more sneezing, runny nose, or itchy eyes than expected. The good news is this effect is short-lived. A simple fix is to separate your orange juice and your Allegra by at least 4 hours. Plain water with your dose is best. If your symptoms aren't controlled, check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Bailey DG, Dresser GK, Munoz C, et al. Reduction of fexofenadine bioavailability by fruit juices. Clin Pharmacol Ther 2001;69:P21.
  2. Lilja JJ, Juntti-Patinen L, Neuvonen PJ. Orange juice substantially reduces the bioavailability of the beta-adrenergic-blocking agent celiprolol. Clin Pharmacol Ther 2004;75:184-90.
  3. Greenblatt DJ. Analysis of drug interactions involving fruit beverages and organic anion-transporting polypeptides. J Clin Pharmacol 2009;49:1403-7. PubMed
  4. Bailey DG. Fruit juice inhibition of uptake transport: a new type of food-drug interaction. Br J Clin Pharmacol 2010;70:645-55. PubMed
Moderate

P-GLYCOPROTEIN SUBSTRATES

2 of 3

Fexofenadine also falls under P-GLYCOPROTEIN SUBSTRATES.

Sweet orange juice seems to modulate P-glycoprotein (P-gp), which might affect the blood levels of P-gp substrates.
Animal and in vitro research suggest that orange juice extract inhibits drug efflux by P-gp, increasing absorption and levels of P-gp substrates. In contrast, pharmacokinetic research in humans shows that drinking large amounts of sweet orange juice decreases absorption and levels of the P-gp substrate celiprolol. This suggests that orange juice actually induces drug efflux by P-gp or affects drug levels by another mechanism such as inhibiting the gut drug transporter called organic anion transporting polypeptide (OATP). Until more is known, sweet orange juice should be used cautiously in people taking P-gp substrates.
Severity Moderate Likelihood Possible Evidence B

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the practical side of this one. Fexofenadine (Allegra) doesn't get broken down much by the liver. Instead, it relies on transporters in your gut, including P-glycoprotein and a related one called OATP, to get into your bloodstream. Sweet orange juice, especially in larger glasses, can interfere with those transporters. The human studies we have suggest orange juice tends to lower how much of certain drugs get absorbed, so your Allegra may not work as well, meaning your runny nose, sneezing, or itchy hives might not be controlled as nicely.

This isn't dangerous, just a possible drop in effectiveness. A simple fix is to take your fexofenadine with water and space it a few hours apart from large amounts of orange juice. Casual amounts with food are unlikely to be a big deal, but check with your pharmacist if you drink a lot.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Bailey DG, Dresser GK, Munoz C, et al. Reduction of fexofenadine bioavailability by fruit juices. Clin Pharmacol Ther 2001;69:P21.
  2. Lilja JJ, Juntti-Patinen L, Neuvonen PJ. Orange juice substantially reduces the bioavailability of the beta-adrenergic-blocking agent celiprolol. Clin Pharmacol Ther 2004;75:184-90.
  3. Tian R, Koyabu N, Takanaga H, et al. Effects of grapefruit juice and orange juice on the intestinal efflux of P-glycoprotein substrates. Pharm Res 2002;19:802-9. PubMed
  4. Takanaga H, Ohnishi A, Yamada S, et al. Polymethoxylated flavones in orange juice are inhibitors of P-glycoprotein but not cytochrome P450 3A4. J Pharmacol Exp Ther 2000;293:230-6. DOI
Moderate

FEXOFENADINE (Allegra)

3 of 3
Consuming sweet orange juice with fexofenadine can decrease oral absorption of fexofenadine.
Clinical research shows that coadministration of sweet orange juice 1200 mL decreases bioavailability of fexofenadine by about 72%. In an animal model, sweet orange juice decreased bioavailability of fexofenadine by 31%. Fexofenadine manufacturer data indicates that concomitant administration of sweet orange juice and fexofenadine results in larger wheal and flare sizes in research models. This suggests that sweet orange reduces the clinical response to fexofenadine. Theoretically, this occurs due to short-term inhibition of organic anion transporting polypeptide (OATP). Recommend separating drug administration and consumption of sweet orange by at least 4 hours.
Severity Moderate Likelihood Likely Evidence B

Well-controlled human studies have demonstrated the likely existence of this interaction.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's something a lot of folks don't realize about Allegra (fexofenadine): washing it down with orange juice can actually make it work less well. Your body relies on little transporters called OATP to shuttle fexofenadine from your gut into your bloodstream. Compounds in sweet orange juice temporarily block those transporters, so less of the drug gets absorbed. In one study, a large glass (about 1200 mL) cut absorption by roughly 72%.

Fexofenadine is not a prodrug, so less absorption simply means a weaker effect. You might notice your hay fever or hives symptoms (sneezing, itching, runny nose) aren't as well controlled. The easy fix is timing: take your Allegra with water and keep orange juice at least 4 hours apart. If your allergies still aren't settling, check in with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Bailey DG, Dresser GK, Munoz C, et al. Reduction of fexofenadine bioavailability by fruit juices. Clin Pharmacol Ther 2001;69:P21.
  2. Greenblatt DJ. Analysis of drug interactions involving fruit beverages and organic anion-transporting polypeptides. J Clin Pharmacol 2009;49:1403-7. PubMed
  3. Bailey DG. Fruit juice inhibition of uptake transport: a new type of food-drug interaction. Br J Clin Pharmacol 2010;70:645-55. PubMed
  4. Kamath AV, Yao M, Zhang Y, Chong S. Effect of fruit juices on the oral bioavailability of fexofenadine in rats. J Pharm Sci 2005;94:233-9. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction 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.
  • PossibleInteraction 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.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Sweet Orange Also Interacts With Other Medications

Sweet Orange has 47 major, 198 moderate known drug interactions in our database — the Fexofenadine one above is among them. If you take anything else, check it against the full list below.

Major 47 Moderate 198 No known interaction 2,585 (incl. Fexofenadine)
Taking anything else?

Check Another of Your Medications Against Sweet Orange

Covers the 2,830 medications we’ve checked against Sweet Orange. Pick one to open its full report.

From our Q&A

Questions About Sweet Orange or Fexofenadine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Sweet Orange or Fexofenadine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Fexofenadine

This page covers Sweet Orange only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fexofenadine page lists 154 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Apple (major), Grapefruit (major), St. John's Wort (major) and Acacia Rigidula (moderate).

By severity: 5 major · 111 moderate · 38 minor.

From our pharmacist’s overview on the Fexofenadine page

“An over-the-counter allergy pill sounds like the last place serious interactions would hide, but fexofenadine (Allegra) has 154 supplements and foods on file, and the five rated major deserve real attention before you combine it with much of anything else. Two of those five sit in most refrigerators.”

Reviewed by 2 · Jul 18, 2026

Open the Fexofenadine interaction page

One more smart check

Taking Sweet Orange as Part of a Dietary Supplement Product? Check It for Interactions

We hold 678 real supplement products containing Sweet Orange, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Sweet Orange. Your product may carry other ingredients that interact with Fexofenadine too, on top of Sweet Orange — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Sweet Orange and Fexofenadine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Sweet Orange
Top 25%

#253 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Fexofenadine
Top 25%

#337 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Sweet Orange

What is Sweet Orange?

Sweet Orange
  • Vitamin C source
  • Digestive upset
  • Stress and relaxation (aromatherapy)
  • Cold and respiratory support
  • Antioxidant support

Sweet orange is a common citrus fruit that is a good source of vitamin C, fiber, and antioxidants, and is enjoyed as a food worldwide. Its peel and essential oil are used in aromatherapy and traditional remedies, but strong scientific proof for most medicinal claims is limited. The fruit and juice are safe for most people as food, while concentrated oils and extracts deserve more caution.

Read the full Sweet Orange monograph & all interactions
Medication

About Fexofenadine

What Is Fexofenadine Used For?

Brand name: Allegra

Fexofenadine temporarily relieves symptoms of hay fever (seasonal allergic rhinitis) and other upper respiratory allergies, including runny nose, sneezing, itchy or watery eyes, and itching of the nose or throat.

Several products — including Allegra Hives 24hr tablets — are specifically used to reduce hives (urticaria) and relieve the itching that comes with them. Keep in mind that fexofenadine will not prevent hives or stop an allergic skin reaction from happening in the first place.

See full Fexofenadine drug information
Keep checking

Other Drugs & Sweet Orange

Browse every other medication we’ve checked against Sweet Orange — both the ones with a known interaction and the ones without. Select any drug for the full detail.

47Major
198Moderate
0Minor
2,584No known interaction
47 Major 198 Moderate 2,584 No interaction
Major

47 interactions

Moderate

198 interactions

Showing 60 of 198 moderate interactions — see all 198 on the Sweet Orange page.

No interaction 2,584 drugs checked — show the list

We also checked Sweet Orange against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,584 medications checked with no known interaction — see the full Sweet Orange list.

See the full Sweet Orange interactions page
See every supplement checked against Fexofenadine, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

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

Keep exploring
Sweet Orange monograph › Uses, safety, and every drug interaction in one place Fexofenadine supplement interactions › Every supplement checked against Fexofenadine, ranked by severity Fexofenadine drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Sweet Orange and Fexofenadine Together: Common Questions

Can you take Sweet Orange with Fexofenadine?
This is rated a major interaction, so the combination is best avoided unless your doctor or pharmacist has specifically told you otherwise. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 3 interactions listed for Sweet Orange and Fexofenadine?
Fexofenadine belongs to more than one drug category, and Sweet Orange interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Sweet Orange and Fexofenadine interaction?
We rate it Major. This is a clinically significant combination that is generally best avoided, or used only under the direct supervision of your physician or pharmacist.

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

Still Have a Question About Fexofenadine and Sweet Orange?

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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.