Drug & supplement interaction

Senna + Warfarin Sodium

Warfarin Sodium brand names: Coumadin, Panwarfin, Sofarin.

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

Senna has a moderate interaction with Warfarin Sodium. Theoretically, excessive use of senna might increase the effects of warfarin.

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

Senna and Warfarin Sodium

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

Moderate

WARFARIN (Coumadin)

Theoretically, excessive use of senna might increase the effects of warfarin.
Senna has stimulant laxative effects and can cause diarrhea. Diarrhea can increase the effects of warfarin, increase international normalized ratio (INR), and increase the risk of bleeding. In one case report, excessive use of senna for 3 weeks resulted in diarrhea, bloody stools, and an elevated INR of 11.9.
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 thing to keep in mind if you take warfarin (Coumadin). Using senna once in a while for short-term constipation is unlikely to cause trouble. The concern comes with heavy or prolonged use, which can lead to ongoing diarrhea. When you have a lot of diarrhea, your body can absorb less vitamin K and your fluid balance shifts, and that can boost warfarin's blood-thinning effect.

In practical terms, that means your INR could climb higher than your target, raising your bleeding risk. Watch for things like easy bruising, bleeding gums, nosebleeds, or blood in the stool. This link is mostly theoretical, with one case report of a very high INR after weeks of overuse. Please don't start or stop anything on your own. Just check with your pharmacist or doctor before using senna regularly.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Kittisupamongkol W, Nilaratanakul V, Kulwichit W. Near-fatal bleeding, senna, and the opposite of lettuce. Lancet 2008;371:784. 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

Senna Also Interacts With Other Medications

Senna has 139 moderate known drug interactions in our database — the Warfarin Sodium one above is one of them. If you take anything else, check it against the full list below.

Moderate 139 No known interaction 2,691 (incl. Warfarin Sodium)
Taking anything else?

Check Another of Your Medications Against Senna

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

From our Q&A

Questions About Senna 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 Senna 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 Senna 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 Senna as Part of a Dietary Supplement Product? Check It for Interactions

We hold 120 real supplement products containing Senna, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Senna. Your product may carry other ingredients that interact with Warfarin Sodium too, on top of Senna — 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 Senna 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 Senna
Top 25%

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

29 days ago today
Medication Warfarin Sodium
Top 1%

#23 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 Senna

What is Senna?

Senna
  • Short-term constipation relief
  • Bowel cleansing before procedures
  • Occasional irregularity
  • Traditional digestive remedy

Senna is a plant-based stimulant laxative that is widely used and generally effective for short-term relief of constipation. It is best used occasionally and for only a few days at a time, since long-term use can lead to dependence and other problems. Talk with a pharmacist or doctor before using it regularly or if you have ongoing constipation.

Read the full Senna monograph & all interactions
Medication

About Warfarin

What Is Warfarin Used For?

Brand names: Coumadin, Panwarfin, Sofarin

Warfarin helps prevent and treat harmful blood clots. The label lists these uses for both Warfarin Sodium tablets and Jantoven tablets:

  • Preventing and treating venous thrombosis (clots in the veins) and pulmonary embolism (clots in the lungs).
  • Preventing and treating clot-related complications of atrial fibrillation and/or heart valve replacement.
  • Lowering the risk of death, another heart attack, and clot-related events such as stroke after a heart attack.

Warfarin does not dissolve a clot that has already formed. It helps stop the clot from growing and prevents further clot-related complications.

See full Warfarin drug information
Keep checking

Other Drugs & Senna

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

0Major
139Moderate
0Minor
2,690No known interaction
139 Moderate 2,690 No interaction
Moderate

139 interactions

Showing 60 of 139 moderate interactions — see all 139 on the Senna page.

No interaction 2,690 drugs checked — show the list

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

Showing the 60 most looked-up of 2,690 medications checked with no known interaction — see the full Senna list.

See the full Senna 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
Senna 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 Senna and Warfarin Sodium Together: Common Questions

Can you take Senna with Warfarin Sodium?
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.
How serious is the Senna and Warfarin Sodium 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 Warfarin Sodium and Senna?

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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.