Drug & supplement interaction

Thyme + Clemastine

Clemastine brand name: Tavist Allergy.

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

Thyme has a moderate interaction with Clemastine. Theoretically, concurrent use of anticholinergic drugs and thyme essential oil might reduce the effects of anticholinergic drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Thyme and Clemastine

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

Moderate

ANTICHOLINERGIC DRUGS

Why this applies to Clemastine

Clemastine falls under ANTICHOLINERGIC DRUGS — the group Thyme interacts with.

Theoretically, concurrent use of anticholinergic drugs and thyme essential oil might reduce the effects of anticholinergic drugs.
In vitro evidence suggests that thyme essential oil and specific essential oil constituents like thymohydroquinone and carvacrol can inhibit acetylcholinesterase (AChE). However, this effect has not been observed in humans.
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 for clemastine (Tavist Allergy). This antihistamine works partly by blocking acetylcholine, which is why it can dry you out and make you sleepy. Concentrated thyme essential oil, in lab dishes, seems to do the opposite by slowing the enzyme that breaks acetylcholine down, leaving more of it around. In theory that could nudge against clemastine and slightly soften its effect.

I want to be honest though: this is only test-tube evidence, and it has not been seen in real people. The thyme you cook with or sip in a tea isn't a worry here. If you're using concentrated thyme oil, just mention it to your pharmacist, but I wouldn't lose sleep over this one.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Jukic, M., Politeo, O., Maksimovic, M., Milos, M., and Milos, M. In vitro acetylcholinesterase inhibitory properties of thymol, carvacrol and their derivatives thymoquinone and thymohydroquinone. Phytother.Res 2007;21(3):259-261.

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

Thyme Also Interacts With Other Medications

Thyme has 378 moderate known drug interactions in our database — the Clemastine one above is one of them. If you take anything else, check it against the full list below.

Moderate 378 No known interaction 2,452 (incl. Clemastine)
Taking anything else?

Check Another of Your Medications Against Thyme

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

From our Q&A

Questions About Thyme or Clemastine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Thyme or Clemastine, 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 Clemastine

This page covers Thyme only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Clemastine page lists 72 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Henbane (major), Scopolia (major), Alfalfa (moderate) and Angel's Trumpet (moderate).

By severity: 3 major · 57 moderate · 12 minor.

From our pharmacist’s overview on the Clemastine page

“Clemastine (Tavist Allergy) is an older, sedating antihistamine that already dries the mouth, blurs vision, and slows the gut, and that is exactly why this list earns real caution rather than a quick skim. Thirty of the 72 supplements on file pile the same drying, sedating anticholinergic load on top, and two of the three major-rated e…”

Reviewed by 2 · Jul 18, 2026

Open the Clemastine interaction page

One more smart check

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

We hold 708 real supplement products containing Thyme, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Thyme. Your product may carry other ingredients that interact with Clemastine too, on top of Thyme — 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 Thyme and Clemastine 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 Thyme
Top 25%

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

29 days ago today
Medication Clemastine
Top half

#1,290 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 Thyme

What is Thyme?

Thyme
  • Cough and respiratory congestion
  • Sore throat
  • Digestive upset
  • Antimicrobial and antiseptic uses
  • Flavoring in cooking

Thyme is a common kitchen herb that has long been used for coughs, sore throats, and digestive complaints. It is generally safe in the amounts found in food, and some cough products that combine thyme with other herbs have modest supporting evidence, but high-quality research on thyme alone is limited. The concentrated essential oil should never be swallowed undiluted.

Read the full Thyme monograph & all interactions
Medication

About Clemastine

What Is Clemastine Used For?

Brand name: Tavist Allergy

Clemastine treats symptoms of allergic rhinitis (hay fever and similar nasal allergies) — including sneezing, runny nose, itching, and watery eyes. The oral solution (Clemastine Fumarate syrup) is indicated for adults and children aged 6 through 12 years. The tablets (Clemastine Fumarate and Clemsza) are indicated for adults.

Clemastine also treats mild, uncomplicated allergic skin reactions — specifically urticaria (hives) and angioedema (swelling under the skin) — at the appropriate dosage level, in both the oral solution and tablet forms.

See full Clemastine drug information
Keep checking

Other Drugs & Thyme

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

0Major
378Moderate
0Minor
2,451No known interaction
378 Moderate 2,451 No interaction
Moderate

378 interactions

Showing 60 of 378 moderate interactions — see all 378 on the Thyme page.

No interaction 2,451 drugs checked — show the list

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

Showing the 60 most looked-up of 2,451 medications checked with no known interaction — see the full Thyme list.

See the full Thyme interactions page
See every supplement checked against Clemastine, 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
Thyme monograph › Uses, safety, and every drug interaction in one place Clemastine supplement interactions › Every supplement checked against Clemastine, ranked by severity Clemastine 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 Thyme and Clemastine Together: Common Questions

Can you take Thyme with Clemastine?
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 Thyme and Clemastine 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 Clemastine and Thyme?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.