Drug & supplement interaction

Tragacanth + Fexofenadine

Fexofenadine brand name: Allegra.

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

Tragacanth has a moderate interaction with Fexofenadine. Theoretically, tragacanth might alter absorption of oral drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Tragacanth and Fexofenadine

Here is the interaction we found between these two, with the evidence behind it.

Moderate

ORAL DRUGS

Why this applies to Fexofenadine

Fexofenadine falls under ORAL DRUGS — the group Tragacanth interacts with.

Theoretically, tragacanth might alter absorption of oral drugs.
Tragacanth contains hydrocolloidal fiber which can decrease, increase, or not affect oral drug absorption. To avoid changes in absorption, take tragacanth 30-60 minutes after oral medications.
Severity Moderate Likelihood Possible Evidence D

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 gist with Allegra (fexofenadine) and tragacanth. Tragacanth is a gummy plant fiber that swells into a thick gel when it hits fluid. When that gel is sitting in your stomach and gut at the same time as a pill, it can sometimes grab onto the medicine and change how much gets absorbed. This is only a theoretical concern based on how the fiber behaves, not something proven in studies, so I wouldn't lose sleep over it.

Fexofenadine is not a prodrug, so the worry here would simply be slightly less of it getting into your system, which could mean weaker relief of your sneezing, runny nose, or itching. An easy fix: take your Allegra first and wait 30 to 60 minutes before the tragacanth. If you're unsure, your pharmacist can help you space them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

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

Tragacanth Also Interacts With Other Medications

Tragacanth has 2,021 moderate known drug interactions in our database — the Fexofenadine one above is one of them. If you take anything else, check it against the full list below.

Moderate 2,021 No known interaction 809 (incl. Fexofenadine)
Taking anything else?

Check Another of Your Medications Against Tragacanth

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

From our Q&A

Questions About Tragacanth 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 Tragacanth 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 Tragacanth 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 Sweet Orange (major).

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 Tragacanth as Part of a Dietary Supplement Product? Check It for Interactions

We hold 34 real supplement products containing Tragacanth, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Tragacanth. Your product may carry other ingredients that interact with Fexofenadine too, on top of Tragacanth — 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 Tragacanth 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 Tragacanth
Top half

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

29 days ago today
Medication Fexofenadine
Top half

#797 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 Tragacanth

What is Tragacanth?

Tragacanth
  • Soothing sore throat and cough
  • Digestive upset and constipation
  • Thickening or binding agent in products
  • Skin soothing in creams and pastes

Tragacanth is a plant gum used mainly as a thickener and emulsifier in foods, cosmetics, and medicines, and traditionally to soothe the throat and gut. There is very little solid human research showing it treats any specific condition. It is generally considered safe in food amounts, but anyone with allergies or who is pregnant or breastfeeding should check with a pharmacist or doctor first.

Read the full Tragacanth 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 & Tragacanth

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

0Major
2,021Moderate
0Minor
808No known interaction
2,021 Moderate 808 No interaction
Moderate

2,021 interactions

Showing 60 of 2,021 moderate interactions — see all 2,021 on the Tragacanth page.

No interaction 808 drugs checked — show the list

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

Showing the 60 most looked-up of 808 medications checked with no known interaction — see the full Tragacanth list.

See the full Tragacanth 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
Tragacanth 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 Tragacanth and Fexofenadine Together: Common Questions

Can you take Tragacanth with Fexofenadine?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Tragacanth and Fexofenadine interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About Fexofenadine and Tragacanth?

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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.