Drug & supplement interaction

Black Pepper + Acenocoumarol

Acenocoumarol brand name: Sintrom.

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

Black Pepper has a moderate interaction with Acenocoumarol. Theoretically, black pepper might increase the risk of bleeding when taken with antiplatelet or anticoagulant drugs.

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

Black Pepper and Acenocoumarol

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

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

Why this applies to Acenocoumarol

Acenocoumarol falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Black Pepper interacts with.

Theoretically, black pepper might increase the risk of bleeding when taken with antiplatelet or anticoagulant drugs.
In vitro research shows that piperine, a constituent of black pepper, seems to inhibit platelet aggregation. This has not been reported in humans.
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 situation with Sintrom (acenocoumarol), which is a blood thinner that's cousin to warfarin. The concern on file is mostly theoretical. In lab dish studies, piperine (the active part of black pepper) seemed to make platelets a little less sticky. That hasn't actually been seen in real people, so think of this as a 'keep an eye out' note, not an alarm.

Because acenocoumarol is already a potent anticoagulant with a narrow safety window, adding a concentrated black pepper or piperine supplement could, in theory, nudge your bleeding risk up. Watch for things like easy bruising, bleeding gums, nosebleeds, or dark stools. The pinch you use in cooking is very unlikely to matter. Before starting a supplement-strength product, check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Raghavendra, R. H. and Naidu, K. A. Spice active principles as the inhibitors of human platelet aggregation and thromboxane biosynthesis. Prostaglandins Leukot.Essent.Fatty Acids 2009;81(1):73-78. 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

Black Pepper Also Interacts With Other Medications

Black Pepper has 975 moderate, 43 minor known drug interactions in our database — the Acenocoumarol one above is one of them. If you take anything else, check it against the full list below.

Moderate 975 Minor 43 No known interaction 1,812 (incl. Acenocoumarol)
Taking anything else?

Check Another of Your Medications Against Black Pepper

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

From our Q&A

Questions About Black Pepper or Acenocoumarol

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

This page covers Black Pepper only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acenocoumarol page lists 221 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), Acetyl-l-carnitine (moderate) and Aconite (moderate).

By severity: 3 major · 193 moderate · 25 minor.

From our pharmacist’s overview on the Acenocoumarol page

“Acenocoumarol (Sintrom) is a blood thinner in the warfarin family, and it lives in a narrow zone where a little too much means bleeding and a little too little means clots. So treat its 221 supplement interactions as a real safety issue, not fine print.”

Reviewed by 2 · Jul 18, 2026

Open the Acenocoumarol interaction page

One more smart check

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

We hold 5,528 real supplement products containing Black Pepper, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Black Pepper. Your product may carry other ingredients that interact with Acenocoumarol too, on top of Black Pepper — 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 Black Pepper and Acenocoumarol 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 Pepper
Top 5%

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

29 days ago today
Medication Acenocoumarol
Top 25%

#539 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 Black Pepper

What is Black Pepper?

Black Pepper
  • Flavoring and culinary use
  • Digestive complaints like bloating and indigestion
  • Boosting absorption of other supplements
  • Antioxidant and anti-inflammatory support
  • Cold and congestion remedies

Black pepper is a common kitchen spice that is generally safe in the amounts used in food. Its extract, piperine, is mostly added to supplements to help the body absorb other ingredients (like curcumin from turmeric). Strong human evidence for black pepper treating specific health conditions is limited, so use supplement-strength products with care and check with your pharmacist.

Read the full Black Pepper monograph & all interactions
Keep checking

Other Drugs & Black Pepper

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

0Major
975Moderate
43Minor
1,811No known interaction
975 Moderate 43 Minor 1,811 No interaction
Moderate

975 interactions

Showing 60 of 975 moderate interactions — see all 975 on the Black Pepper page.

Minor

43 interactions

No interaction 1,811 drugs checked — show the list

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

Showing the 60 most looked-up of 1,811 medications checked with no known interaction — see the full Black Pepper list.

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

Can you take Black Pepper with Acenocoumarol?
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 Black Pepper and Acenocoumarol 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 Acenocoumarol and Black Pepper?

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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.