Drug & supplement interaction

Mullein + Warfarin

Warfarin brand name: Warfarin.

Minor Interaction
Medically reviewed by · Updated April 2024
The bottom line Minor

Mullein has a minor interaction with Warfarin. Lab tests on extracts from different parts of common and dense-flowered mullein plants show that they do have some blood-thinning effects, as they increase the time it takes for blood to clot.

Read the full interaction report
SeverityMinor
LikelihoodUnlikely
EvidenceA
What do Severity, Likelihood & Evidence mean?
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Interaction report

Mullein and Warfarin

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

Minor

Anticoagulant/Antiplatelet Drugs

Why this applies to Warfarin

Warfarin falls under Anticoagulant/Antiplatelet Drugs — the group Mullein interacts with.

Lab tests on extracts from different parts of common and dense-flowered mullein plants show that they do have some blood-thinning effects, as they increase the time it takes for blood to clot. This is likely due to at least one of the known constituents of muellein, triterpenoid saponins. However, the effects appear to be mild and results have been inconsistent. Extracts from different plant parts have been show to have varying anticoagulant strengths, with water-based ones being more potent than alcohol-based extracts.
Severity Minor Likelihood Unlikely Evidence A

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

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

Here's the situation with mullein and your warfarin. In the test tube, some mullein extracts have shown a mild blood-thinning effect of their own, likely from plant compounds called triterpenoid saponins. In theory, that could add to what warfarin is already doing, nudging you toward easier bruising, nosebleeds, or bleeding gums.

That said, I don't want to overstate this. The lab results were mild and inconsistent, and this isn't a strong real-world concern. Still, warfarin is one of those drugs where even small shifts matter, and your dose is tracked closely with INR blood tests. Please don't start or stop mullein on your own. Just give your pharmacist or doctor a heads-up first so they can keep an eye on your numbers.

Contact Dr. Brian directly if you have additional questions on this interaction

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

Mullein Also Interacts With Other Medications

Mullein has 121 minor known drug interactions in our database — the Warfarin one above is one of them. If you take anything else, check it against the full list below.

Minor 121 No known interaction 2,709 (incl. Warfarin)
Taking anything else?

Check Another of Your Medications Against Mullein

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

From our Q&A

Questions About Mullein or Warfarin

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

This page covers Mullein only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Warfarin page lists 361 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Alfalfa (major), American Ginseng (major), Beer (major) and Cannabis (major).

By severity: 16 major · 301 moderate · 44 minor.

From our pharmacist’s overview on the Warfarin page

“People take warfarin to prevent dangerous clots, and many are the same people reaching for glucosamine for sore joints or a multivitamin containing vitamin K, which makes this a list that deserves genuine respect. Of the 361 supplements on file for warfarin, 16 carry a major rating, and the danger runs in both directions: some add to w…”

Reviewed by 2 · Jul 18, 2026

Open the Warfarin interaction page

One more smart check

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

We hold 780 real supplement products containing Mullein, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Mullein. Your product may carry other ingredients that interact with Warfarin too, on top of Mullein — 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 Mullein and Warfarin 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 Mullein
Top 25%

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

29 days ago today
Medication Warfarin
Top 10

#5 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 Mullein

What is Mullein?

Mullein
  • Cough and chest congestion
  • Sore throat
  • Bronchitis and respiratory irritation
  • Earache (traditional ear oil)
  • Mild inflammation

Mullein is a traditional herbal remedy most often used as a tea or syrup to soothe coughs, sore throats, and respiratory irritation. High-quality human studies are lacking, so its benefits are not well proven, but it is generally considered low-risk for short-term use in healthy adults. Talk to your pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or have a medical condition.

Read the full Mullein monograph & all interactions
Medication

About Warfarin

What Is Warfarin Used For?

Brand name: Warfarin

Warfarin sodium tablets and Jantoven tablets are both used to prevent and treat venous thrombosis (blood clots in the veins) and pulmonary embolism (a clot in the lungs). They are also used to prevent clot-related complications in people with atrial fibrillation (an irregular heart rhythm) or who have had a heart valve replaced.

In people who have had a heart attack, warfarin is used to reduce the risk of death, another heart attack, stroke, or other clotting events. It does not dissolve an existing clot, but it helps prevent the clot from growing and stops new dangerous clots from forming.

See full Warfarin drug information
Keep checking

Other Drugs & Mullein

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

0Major
0Moderate
121Minor
2,708No known interaction
121 Minor 2,708 No interaction
Minor

121 interactions

Showing 60 of 121 minor interactions — see all 121 on the Mullein page.

No interaction 2,708 drugs checked — show the list

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

Showing the 60 most looked-up of 2,708 medications checked with no known interaction — see the full Mullein list.

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

Can you take Mullein with Warfarin?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Mullein and Warfarin interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Warfarin and Mullein?

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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.