Drug & supplement interaction

Saw Palmetto + Antithrombin III

Antithrombin III brand name: Thrombate III.

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

Saw Palmetto has a moderate interaction with Antithrombin III. Saw palmetto might increase the risk of bleeding with anticoagulant or antiplatelet drugs.

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

Saw Palmetto and Antithrombin III

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

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

Why this applies to Antithrombin III

Antithrombin III falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Saw Palmetto interacts with.

Saw palmetto might increase the risk of bleeding with anticoagulant or antiplatelet drugs.
Saw palmetto is reported to prolong bleeding time. Theoretically, it might increase the risk of bleeding when used concomitantly with anticoagulant or antiplatelet drugs.
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

Antithrombin III (Thrombate III) is a blood-thinning protein given to lower clotting risk, especially in people with an inherited antithrombin deficiency during surgery or childbirth. Anything that adds to its blood-thinning power could tip you toward bleeding more easily. That is where saw palmetto comes in.

There are scattered reports that saw palmetto can lengthen bleeding time, so in theory pairing it with antithrombin III might raise your bleeding risk a little (think easy bruising, nosebleeds, or bleeding that takes longer to stop). I'll be honest: this is based on weak, anecdotal evidence, not strong studies, so it's more of a caution than a sure thing. Still, since antithrombin III is usually used around procedures, please let your doctor or pharmacist know you take saw palmetto before they dose it.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Cheema P, El-Mefty O, Jazieh AR. Intraoperative haemorrhage associated with the use of extract of Saw Palmetto herb: a case report and review of literature. J Intern Med 2001;250:167-9. 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

Saw Palmetto Also Interacts With Other Medications

Saw Palmetto has 173 moderate known drug interactions in our database — the Antithrombin III one above is one of them. If you take anything else, check it against the full list below.

Moderate 173 No known interaction 2,657 (incl. Antithrombin III)
Taking anything else?

Check Another of Your Medications Against Saw Palmetto

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

From our Q&A

Questions About Saw Palmetto or Antithrombin III

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

This page covers Saw Palmetto only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Antithrombin III 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.

Open the Antithrombin III interaction page

One more smart check

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

We hold 3,466 real supplement products containing Saw Palmetto, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Saw Palmetto. Your product may carry other ingredients that interact with Antithrombin III too, on top of Saw Palmetto — 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 Saw Palmetto and Antithrombin III 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 Saw Palmetto
Top 10%

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

29 days ago today
Medication Antithrombin III
Steady interest

#1,422 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 Saw Palmetto

What is Saw Palmetto?

Saw Palmetto
  • Benign prostatic hyperplasia (BPH) symptoms
  • Urinary problems
  • Hair loss
  • Prostate health
  • Inflammation

Saw palmetto is a plant extract most often used for urinary symptoms linked to an enlarged prostate (BPH). The best research suggests it works no better than a placebo for most men, though it is generally well tolerated. Talk to your doctor or pharmacist before using it, especially for prostate or urinary problems that need proper evaluation.

Read the full Saw Palmetto monograph & all interactions
Keep checking

Other Drugs & Saw Palmetto

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

0Major
173Moderate
0Minor
2,656No known interaction
173 Moderate 2,656 No interaction
Moderate

173 interactions

Showing 60 of 173 moderate interactions — see all 173 on the Saw Palmetto page.

No interaction 2,656 drugs checked — show the list

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

Showing the 60 most looked-up of 2,656 medications checked with no known interaction — see the full Saw Palmetto list.

See the full Saw Palmetto interactions page
See every supplement checked against Antithrombin III, 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
Saw Palmetto monograph › Uses, safety, and every drug interaction in one place Antithrombin III supplement interactions › Every supplement checked against Antithrombin III, 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 Saw Palmetto and Antithrombin III Together: Common Questions

Can you take Saw Palmetto with Antithrombin III?
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 Saw Palmetto and Antithrombin III 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 Antithrombin III and Saw Palmetto?

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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.