Drug & supplement interaction

Ashwagandha + Warfarin Sodium

Warfarin Sodium brand names: Coumadin, Panwarfin, Sofarin.

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

Warfarin Sodium falls into 2 drug categories that Ashwagandha can interact with; the most serious is rated minor. Theoretically, ashwagandha might decrease the levels and clinical effects of CYP1A2 substrates.

Read the full interaction report
SeverityMinor
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Ashwagandha and Warfarin Sodium

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Ashwagandha interacts with whole categories of medication. Warfarin Sodium falls into 2 of those categories, so it can interact with Ashwagandha in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Minor).

Minor

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

1 of 2

Why this applies to Warfarin Sodium

Warfarin Sodium falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Ashwagandha interacts with.

Theoretically, ashwagandha might decrease the levels and clinical effects of CYP1A2 substrates.
In vitro research shows that ashwagandha extract induces CYP1A2 enzymes.
Severity Minor 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 warfarin (Coumadin). Lab studies hint that ashwagandha may speed up a liver enzyme called CYP1A2, which is one of the pathways that helps clear warfarin. In theory, that could lower your warfarin levels a bit, meaning your blood might clot a little more easily and you could lose some protection against clots. Warfarin is a narrow-therapeutic-index drug, so even small shifts can nudge your INR off target.

That said, this is only a theoretical, test-tube finding, not something proven in people, so I wouldn't panic. If you and your doctor decide to add ashwagandha, the smart move is simply to keep up with your regular INR checks and let your pharmacist know so they can watch the numbers.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Haron MH, Dale O, Martin K, et al. Evaluation of the Herb-Drug Interaction Potential of Commonly Used Botanicals on the US Market with Regard to PXR- and AhR-Mediated Influences on CYP3A4 and CYP1A2. J Diet Suppl 2022. PubMed
Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

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

Theoretically, ashwagandha might decrease the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that ashwagandha extract induces CYP3A4 enzymes.
Severity Minor 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 thinking on combining ashwagandha with warfarin. Some lab research suggests ashwagandha may speed up an enzyme called CYP3A4, which is one of the pathways your body uses to clear warfarin. If that happened in real life, your warfarin could clear a little faster, which might weaken its blood-thinning effect and leave you slightly less protected against clots.

I want to be honest: this is only a theoretical concern based on test-tube and animal data, not human studies, so it may not matter much at all. But warfarin is a finicky drug where even small shifts can change your INR. Before adding ashwagandha, check with your pharmacist or doctor, and keep up with your regular INR testing so any change gets caught early.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Haron MH, Dale O, Martin K, et al. Evaluation of the Herb-Drug Interaction Potential of Commonly Used Botanicals on the US Market with Regard to PXR- and AhR-Mediated Influences on CYP3A4 and CYP1A2. J Diet Suppl 2022. 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

Ashwagandha Also Interacts With Other Medications

Ashwagandha has 916 moderate, 455 minor known drug interactions in our database — the Warfarin Sodium one above is among them. If you take anything else, check it against the full list below.

Moderate 916 Minor 455 No known interaction 1,459 (incl. Warfarin Sodium)
Taking anything else?

Check Another of Your Medications Against Ashwagandha

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

From our Q&A

Questions About Ashwagandha or Warfarin Sodium

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

This page covers Ashwagandha only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Warfarin Sodium 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).

Open the Warfarin Sodium interaction page

One more smart check

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

We hold 4,964 real supplement products containing Ashwagandha, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Ashwagandha. Your product may carry other ingredients that interact with Warfarin Sodium too, on top of Ashwagandha — 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 Ashwagandha and Warfarin Sodium 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 Ashwagandha
Top 5%

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

29 days ago today
Medication Warfarin Sodium
Top 1%

#19 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 Ashwagandha

What is Ashwagandha?

Ashwagandha
  • Stress and anxiety
  • Sleep problems
  • Fatigue and low energy
  • Athletic performance
  • General well-being (adaptogen)

Ashwagandha is an Ayurvedic herb most often taken to help with stress, anxiety, and sleep, and some small studies suggest it may help, though the evidence is still limited. It is generally well tolerated for short-term use in healthy adults, but it should be avoided in pregnancy and used cautiously by people with thyroid or liver problems. Talk with your pharmacist or doctor before starting it.

Read the full Ashwagandha monograph & all interactions
Medication

About Warfarin

What Is Warfarin Used For?

Brand names: Coumadin, Panwarfin, Sofarin

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 & Ashwagandha

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

0Major
916Moderate
455Minor
1,458No known interaction
916 Moderate 455 Minor 1,458 No interaction
Moderate

916 interactions

Showing 60 of 916 moderate interactions — see all 916 on the Ashwagandha page.

Minor

455 interactions

Showing 60 of 455 minor interactions — see all 455 on the Ashwagandha page.

No interaction 1,458 drugs checked — show the list

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

Showing the 60 most looked-up of 1,458 medications checked with no known interaction — see the full Ashwagandha list.

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

Can you take Ashwagandha with Warfarin Sodium?
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.
Why are there 2 interactions listed for Ashwagandha and Warfarin Sodium?
Warfarin Sodium belongs to more than one drug category, and Ashwagandha 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 Ashwagandha and Warfarin Sodium 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 Sodium and Ashwagandha?

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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.