Drug & supplement interaction

Peppermint + Diazepam

Diazepam brand names: Valium, Valium injection, Diastat AcuDial, Valtoco.

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

Diazepam falls into 4 drug categories that Peppermint can interact with; the most serious is rated moderate. Theoretically, peppermint might increase the levels of CYP2C19 substrates.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions4
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Peppermint and Diazepam

These two interact in 4 distinct ways. Each one is explained separately below.

Why Are There 4 Interactions?

Peppermint interacts with whole categories of medication. Diazepam falls into 4 of those categories, so it can interact with Peppermint in 4 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES

1 of 4

Why this applies to Diazepam

Diazepam falls under CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES — the group Peppermint interacts with.

Theoretically, peppermint might increase the levels of CYP2C19 substrates.
In vitro research shows that peppermint oil inhibits CYP2C19. So far, this interaction has not been reported 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: your body uses an enzyme called CYP2C19 to help clear diazepam (Valium) out of your system. In lab studies, peppermint oil seems to slow that same enzyme down. If that happened in real life, diazepam could hang around a bit longer than usual, which might mean stronger effects like extra drowsiness, dizziness, foggy thinking, or feeling unsteady on your feet.

The reassuring part is that this is only a theoretical concern. It has been seen in test tubes, not in actual people, and a peppermint candy or a cup of tea is very unlikely to matter. Concentrated peppermint oil capsules are where I'd pay more attention. If you take both regularly, just give your pharmacist or doctor a quick heads-up so they can keep an eye on how you feel.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1 PubMed
Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

2 of 4

Diazepam also falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES.

Theoretically, peppermint might increase the levels of CYP2C9 substrates.
In vitro research shows that peppermint oil inhibits CYP2C9. So far, this interaction has not been reported 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 diazepam (Valium): your liver uses an enzyme called CYP2C9 (among others) to help break it down. In lab dish studies, peppermint oil appears to slow that enzyme down a bit. In theory, that could let diazepam clear a little slower and build up, which might mean more drowsiness, dizziness, grogginess, or trouble with coordination than usual.

That said, I want to keep this in perspective. This is theoretical and based only on test-tube data. It has not actually been reported in real people, and an occasional cup of peppermint tea is very unlikely to matter. Concentrated peppermint oil capsules taken regularly are the bigger question mark. If you use those routinely, just run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1 PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 4

Diazepam also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, peppermint might increase the levels of CYP3A4 substrates.
Clinical research in healthy volunteers shows that a single dose of peppermint oil 600 mg inhibits CYP3A4 enzymes and increases the AUC of felodipine, a CYP3A4 substrate. However, in vitro research suggests that peppermint oil only inhibits CYP3A4 at very high concentrations.
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

Your body relies partly on an enzyme called CYP3A4 to clear diazepam (Valium) out of your system. Peppermint oil, in concentrated supplement form, can mildly slow that same enzyme down. In theory, that means diazepam could hang around a bit longer and build up, which might make its effects stronger than expected. Think more drowsiness, dizziness, grogginess, or feeling unsteady on your feet.

The good news is the evidence here is on the weaker side, and most studies suggest peppermint only blocks this enzyme at fairly high doses. A peppermint tea or a candy is very unlikely to matter. If you regularly take enteric-coated peppermint oil capsules for IBS, just mention it to your pharmacist or doctor so they can keep an eye on how you feel.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Dresser GK, Wacher V, Wong S, et al. Evaluation of peppermint oil and ascorbyl palmitate as inhibitors of cytochrome P4503A4 activity in vitro and in vivo. Clin Pharmacol Ther 2002;72:247-55. PubMed
  2. Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1 PubMed
Minor

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

4 of 4

Diazepam also falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES.

Theoretically, peppermint might increase the levels of CYP1A2 substrates.
In vitro and animal research shows that peppermint oil and peppermint leaf inhibit CYP1A2. However, in clinical research, peppermint tea did not significantly affect the metabolism of caffeine, a CYP1A2 substrate. It is possible that the 6-day duration of treatment may have been too short to identify a difference.
Severity Minor 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 gist for Valium (diazepam) and peppermint. In lab and animal studies, peppermint can slow down an enzyme called CYP1A2. If that enzyme helped clear diazepam, the medicine could build up a bit, which in theory might mean more drowsiness, dizziness, or feeling foggy. Diazepam is a regular active drug (not a prodrug), so blocking its breakdown would lean toward a stronger effect, not a weaker one.

The honest part: this is mostly theoretical. When peppermint tea was tested in people, it didn't meaningfully change how the body handled a similar CYP1A2 drug. Everyday culinary peppermint is unlikely to cause trouble, though concentrated oil capsules are stronger. If you take diazepam daily, just run it by your pharmacist or doctor before starting peppermint supplements.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1 PubMed
  2. Maliakal PP, Wanwimolruk S. Effect of herbal teas on hepatic drug metabolizing enzymes in rats. J Pharm Pharmacol 2001;53:1323-9. PubMed
  3. Begas E, Tsioutsiouliti A, Kouvaras E, et al. Effects of peppermint tea consumption on the activities of CYP1A2, CYP2A6, Xanthine Oxidase, N-acetyltranferase-2 and UDP-glucuronosyltransferases-1A1/1A6 in healthy volunteers. Food Chem Toxicol 2017;100:80-9 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

Peppermint Also Interacts With Other Medications

Peppermint has 732 moderate, 65 minor known drug interactions in our database — the Diazepam one above is among them. If you take anything else, check it against the full list below.

Moderate 732 Minor 65 No known interaction 2,033 (incl. Diazepam)
Taking anything else?

Check Another of Your Medications Against Peppermint

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

From our Q&A

Questions About Peppermint or Diazepam

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

This page covers Peppermint only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diazepam page lists 244 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Grapefruit (major).

By severity: 9 major · 191 moderate · 44 minor.

Open the Diazepam interaction page

One more smart check

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

We hold 1,980 real supplement products containing Peppermint, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Peppermint. Your product may carry other ingredients that interact with Diazepam too, on top of Peppermint — 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 Peppermint and Diazepam 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 Peppermint
Top 10%

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

29 days ago today
Medication Diazepam
Top 10%

#222 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 Peppermint

What is Peppermint?

Peppermint
  • Irritable bowel syndrome (IBS)
  • Indigestion and gas
  • Nausea
  • Tension headache (topical oil)
  • Colds and congestion
  • Freshening breath

Peppermint is a popular herb with the best evidence supporting enteric-coated peppermint oil for easing IBS symptoms. It is generally well tolerated for most adults, but it can cause heartburn and is not recommended in concentrated oil form for infants and young children. Check with your pharmacist or doctor before using it regularly, especially during pregnancy or breastfeeding.

Read the full Peppermint monograph & all interactions
Medication

About Diazepam

What Is Diazepam Used For?

Brand names: Valium, Valium injection, Diastat AcuDial, Valtoco

Diazepam treats several different problems, depending on the product. Oral diazepam (tablets such as Valium, and oral solution) is used for anxiety disorders, short-term relief of anxiety symptoms, and symptom relief in acute alcohol withdrawal. It is also used alongside other treatments for muscle spasm and, adjunctively, for convulsive disorders (seizure disorders).

Diazepam injection is used for the same anxiety and alcohol withdrawal uses. It is also used before endoscopic procedures, before surgery, and before cardioversion (when given intravenously). It helps with muscle spasm and tetanus, and with status epilepticus (a prolonged, dangerous seizure) as an add-on. Diazepam rectal gel and Valtoco nasal spray are used only for seizure clusters (acute repetitive seizures) in people with epilepsy ages 2 and older.

See full Diazepam drug information
Keep checking

Other Drugs & Peppermint

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

0Major
732Moderate
65Minor
2,032No known interaction
732 Moderate 65 Minor 2,032 No interaction
Moderate

732 interactions

Showing 60 of 732 moderate interactions — see all 732 on the Peppermint page.

Minor

65 interactions

Showing 60 of 65 minor interactions — see all 65 on the Peppermint page.

No interaction 2,032 drugs checked — show the list

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

Showing the 60 most looked-up of 2,032 medications checked with no known interaction — see the full Peppermint list.

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

Can you take Peppermint with Diazepam?
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.
Why are there 4 interactions listed for Peppermint and Diazepam?
Diazepam belongs to more than one drug category, and Peppermint 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 Peppermint and Diazepam 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 Diazepam and Peppermint?

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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.