Drug & supplement interaction

Black Horehound + Mephenytoin

Mephenytoin brand name: Mesantoin.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Black Horehound and Mephenytoin in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Black Horehound and Mephenytoin

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Mephenytoin and Black Horehound in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Black Horehound safety at a glance

Black Horehound overall Use caution Limited safety data exist, so use cautiously and talk to a pharmacist first.
Pregnancy Likely Unsafe When used orally; black horehound may affect the menstrual cycle. There is insufficient reliable information available about the safety of black horehound used... Read the full pregnancy detail
Breastfeeding Avoid Safety is unknown, so avoid use while breastfeeding.

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Mephenytoin and Black Horehound? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Mephenytoin

Interactions in our licensed database are recorded against drug classes, not just single drug names. Mephenytoin is filed under 11 classifications — including anticonvulsants, cytochrome p450 2c19 (cyp2c19) inducers, cytochrome p450 1a2 (cyp1a2) inducers. Black Horehound has documented interactions with 1 drug class — the most serious being dopamine agonists (moderate) — and none of Mephenytoin’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Black Horehound Does Interact With Other Medications

Black Horehound has 23 moderate known drug interactions in our database — Mephenytoin isn’t one of them. If you take anything else, check it against the full list below.

Moderate 23 No known interaction 2,807 (incl. Mephenytoin)
Taking anything else?

Check Another of Your Medications Against Black Horehound

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

Special populations

Black Horehound in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used orally; black horehound may affect the menstrual cycle. There is insufficient reliable information available about the safety of black horehound used topically or rectally during pregnancy.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Everything else you take

See Every Supplement That Interacts With Mephenytoin

This page covers Black Horehound only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Mephenytoin page lists 215 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 Kava (major).

By severity: 9 major · 178 moderate · 28 minor.

From our pharmacist’s overview on the Mephenytoin page

“Anyone taking mephenytoin (Mesantoin) for seizures should read this page with genuine care rather than as background noise. The biggest cluster of interactions piles sedation on top of a drug that already slows the nervous system, and alcohol, whether beer or wine, sits at the serious end of that group.”

Reviewed by 2 · Jul 18, 2026

Open the Mephenytoin interaction page

How much people look this up

Where Black Horehound and Mephenytoin 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 Black Horehound
Steady interest

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

29 days ago today
Medication Mephenytoin
Top half

#1,344 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Black Horehound reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Black Horehound and Mephenytoin records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Black Horehound

What is Black Horehound?

Black Horehound
  • Nausea and vomiting
  • Anxiety and nervous tension
  • Sleep problems
  • Mild digestive upset
  • Coughs and respiratory complaints

Black horehound is a traditional European herb mainly used for nausea, mild anxiety, and digestive upset, but high-quality human studies are lacking, so its effectiveness is largely unproven. It has a strong, unpleasant smell and taste, and its safety has not been well studied, so it should be avoided in pregnancy and breastfeeding and used cautiously by everyone else.

Ballota nigra · Lamiaceae · Above-ground parts (flowering tops and leaves) · Tea (infusion), liquid extract, tincture, capsules

An interaction check asks whether these two react with each other — it does not ask whether Black Horehound is a good idea for someone in your situation. Here is what our Black Horehound record says about it on its own.

Black Horehound: dosing

There is no well-established, standardized dose for black horehound. Traditional use has involved teas made from the dried herb and liquid extracts or tinctures, but reliable dosing from quality human studies is not available.If you choose to use a product, follow the directions on the label and do not exceed the recommended amount.

From our Black Horehound monograph — the full record covers uses, side effects and every documented interaction.

Read the full Black Horehound monograph & all interactions
Keep checking

Other Drugs & Black Horehound

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

0Major
23Moderate
0Minor
2,806No known interaction
23 Moderate 2,806 No interaction
Moderate

23 interactions

No interaction 2,806 drugs checked — show the list

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

Showing the 60 most looked-up of 2,806 medications checked with no known interaction — see the full Black Horehound list.

See the full Black Horehound interactions page
See every supplement checked against Mephenytoin, ranked by severity
Evidence & sources

Black Horehound References

The 2 references that drive our Black Horehound monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. Daels-Rakotoarison DA, Seidel V, Gressier B, et al. Neurosedative and antioxidant activities of phenylpropanoids from Ballota nigra. Arzneimittelforschung 2000;50:16-23. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Black Horehound and Mephenytoin Together: Common Questions

Is it safe to take Black Horehound with Mephenytoin?
We do not list a known interaction between Black Horehound and Mephenytoin. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
How was the Black Horehound and Mephenytoin combination checked?
Interactions in our licensed database are recorded against drug classes. Mephenytoin is filed under 11 classifications, and Black Horehound has documented interactions with 1 drug class — none of Mephenytoin's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Black Horehound interact with any other medications?
Yes. Black Horehound has 23 documented drug interactions in our database — Mephenytoin is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Mephenytoin interact with any supplements?
Yes. Mephenytoin has documented interactions with 215 supplements in our database — Black Horehound is not one of them. The Mephenytoin interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Black Horehound monograph Uses, safety profile, and every drug interaction in one place Mephenytoin supplement interactions Every supplement checked against Mephenytoin, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Mephenytoin and Black Horehound?

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.