Drug & supplement interaction

Mullein + Dicumarol

Dicumarol brand name: Dicumarol.

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

Mullein has a minor interaction with Dicumarol. 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 Dicumarol

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

Minor

Anticoagulant/Antiplatelet Drugs

Why this applies to Dicumarol

Dicumarol 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 gist if you take Dicumarol, a blood thinner, along with mullein tea or syrup. Lab studies suggest mullein has a mild blood-thinning effect of its own, likely from plant compounds called triterpenoid saponins. In theory, stacking that on top of Dicumarol could nudge your blood toward thinning a little more than expected, which raises the chance of bruising, nosebleeds, or bleeding gums.

That said, the evidence here is weak and inconsistent, coming from test-tube work rather than people, and the effect looks small. Dicumarol is a narrow-margin drug, though, so even modest shifts matter. Since your dose is guided by INR blood tests, please loop in your pharmacist or doctor before starting mullein so they can watch 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 Dicumarol 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. Dicumarol)
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 Dicumarol

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 Dicumarol, 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 Dicumarol

This page covers Mullein only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Dicumarol page lists 218 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Danshen (major), Piracetam (major), Aconite (moderate) and Allspice (moderate).

By severity: 3 major · 190 moderate · 25 minor.

From our pharmacist’s overview on the Dicumarol page

“Danshen tops my worry list for anyone taking dicumarol, an older blood thinner in the warfarin family. It has clot-blocking activity of its own, and stacking it on an anticoagulant can push bleeding risk too far.”

Reviewed by 2 · Jul 18, 2026

Open the Dicumarol 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 Dicumarol 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 Dicumarol 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 Dicumarol
Steady interest

#2,200 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
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 Dicumarol, 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 Dicumarol supplement interactions › Every supplement checked against Dicumarol, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Mullein and Dicumarol Together: Common Questions

Can you take Mullein with Dicumarol?
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 Dicumarol 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 Dicumarol 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.