Drug & supplement interaction

Sweet Woodruff + Pentoxifylline

Pentoxifylline brand name: Trental.

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

Sweet Woodruff has a moderate interaction with Pentoxifylline. Theoretically, concomitant use might increase the effects of some anticoagulant and antiplatelet drugs and increase the risk of bleeding.

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

Sweet Woodruff and Pentoxifylline

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

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

Why this applies to Pentoxifylline

Pentoxifylline falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Sweet Woodruff interacts with.

Theoretically, concomitant use might increase the effects of some anticoagulant and antiplatelet drugs and increase the risk of bleeding.
Sweet woodruff contains coumarin and coumarin derivatives. However, the levels of coumarin found in sweet woodruff are so low that clinically relevant effects are doubtful. Until more is known, use with caution.
Severity Moderate Likelihood Unlikely Evidence D

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 basic idea: pentoxifylline already thins your blood a little to help it move through narrow vessels in your hands and feet. Sweet woodruff carries a natural compound called coumarin, which can have a mild blood-thinning effect of its own. Stack the two together and, in theory, you could nudge up the risk of bleeding or bruising, things like nosebleeds, easy bruises, or bleeding gums.

That said, I don't want to over-worry you. This is a theoretical concern only, based on how the herb behaves on paper. The amount of coumarin in sweet woodruff is usually very low, so a real problem is unlikely, especially with culinary or occasional use. Concentrated supplement doses are where I'd be more cautious. Either way, it's worth a quick chat with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  2. Sulma, T. and Wierzchowska, K. [Studies on the content of coumarin in the herbs of the woodruff (Herba Asperulae odoratae) throughout the vegetative period of the plant.]. Acta Pol.Pharm 1963;20:77-82.
  3. Kovac-Besovic, E. E. and Duric, K. Thin layer chromatography-application in qualitative analysis on presence of coumarins and flavonoids in plant material. Bosn.J Basic Med.Sci. 2003;3(3):19-26. PubMed
  4. Kahkeshani N, Farahanikia B, Mahdaviani P, et al. Antioxidant and burn healing potential of Galium odoratum extracts. Res Pharm Sci 2013;8(3):197-203.

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

Sweet Woodruff Also Interacts With Other Medications

Sweet Woodruff has 121 moderate known drug interactions in our database — the Pentoxifylline one above is one of them. If you take anything else, check it against the full list below.

Moderate 121 No known interaction 2,709 (incl. Pentoxifylline)
Taking anything else?

Check Another of Your Medications Against Sweet Woodruff

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

Everything else you take

See Every Supplement That Interacts With Pentoxifylline

This page covers Sweet Woodruff only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Pentoxifylline 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 Pentoxifylline page

“Pentoxifylline (Trental) improves blood flow in people with poor leg circulation partly by making platelets less sticky, so treat this list as one to read carefully rather than skim. Of the 218 supplements on file, 202 can also slow clotting, which means adding them stacks bleeding risk on bleeding risk.”

Reviewed by 2 · Jul 18, 2026

Open the Pentoxifylline interaction page

One more smart check

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

We hold 27 real supplement products containing Sweet Woodruff, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Sweet Woodruff. Your product may carry other ingredients that interact with Pentoxifylline too, on top of Sweet Woodruff — 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 Sweet Woodruff and Pentoxifylline 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 Sweet Woodruff
Steady interest

#1,052 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Pentoxifylline
Top half

#862 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 Sweet Woodruff

What is Sweet Woodruff?

Sweet Woodruff
  • Digestive upset
  • Anxiety, restlessness, and sleep
  • Liver and gallbladder complaints
  • Urinary tract problems
  • Respiratory complaints
  • As a flavoring agent

Sweet woodruff is a fragrant European herb traditionally used for digestion, calming, and various other complaints, but solid human evidence for any of these uses is lacking. It contains coumarin, which can be harmful in large amounts, so it should be used only sparingly and avoided during pregnancy and breastfeeding. Talk to your pharmacist or doctor before using it.

Read the full Sweet Woodruff monograph & all interactions
Medication

About Pentoxifylline

What Is Pentoxifylline Used For?

Brand name: Trental

Pentoxifylline Extended-Release Tablets are used to treat intermittent claudication — leg pain, cramping, or fatigue that happens during walking because narrowed arteries aren't delivering enough blood to the muscles. The underlying cause is chronic occlusive arterial disease, a condition where the arteries in the limbs become blocked or narrowed over time.

Pentoxifylline can help improve walking distance and reduce symptoms, but it is not a substitute for procedures that physically open or bypass blocked arteries when those treatments are needed.

See full Pentoxifylline drug information
Keep checking

Other Drugs & Sweet Woodruff

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

0Major
121Moderate
0Minor
2,708No known interaction
121 Moderate 2,708 No interaction
Moderate

121 interactions

Showing 60 of 121 moderate interactions — see all 121 on the Sweet Woodruff page.

No interaction 2,708 drugs checked — show the list

We also checked Sweet Woodruff 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 Sweet Woodruff list.

See the full Sweet Woodruff interactions page
See every supplement checked against Pentoxifylline, 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
Sweet Woodruff monograph › Uses, safety, and every drug interaction in one place Pentoxifylline supplement interactions › Every supplement checked against Pentoxifylline, ranked by severity Pentoxifylline 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 Sweet Woodruff and Pentoxifylline Together: Common Questions

Can you take Sweet Woodruff with Pentoxifylline?
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 Sweet Woodruff and Pentoxifylline 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 Pentoxifylline and Sweet Woodruff?

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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.