Drug & supplement interaction

Cocoa + Pentoxifylline

Pentoxifylline brand name: Trental.

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

Cocoa has a moderate interaction with Pentoxifylline. Theoretically, cocoa may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Cocoa 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 Cocoa interacts with.

Theoretically, cocoa may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Clinical research shows that intake of cocoa can inhibit platelet adhesion, aggregation, and activity and increase aspirin-induced bleeding time. For patients on dual antiplatelet therapy, cocoa may enhance the inhibitory effect of clopidogrel, but not aspirin, on platelet aggregation.
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 gist: pentoxifylline (Trental) works by making your blood less thick and easier to pump through small vessels, which gives it a mild blood-thinning quality. Cocoa contains flavanols that, in lab and some human studies, appear to make platelets a little less sticky. Stack the two together and you may nudge your bleeding risk up a touch, so you might notice easier bruising, nosebleeds, or bleeding gums.

I want to be honest about the strength of this: it's theoretical, based mostly on how these compounds behave, not on strong studies with this exact drug. A cup of hot cocoa or a square of chocolate is very unlikely to cause trouble. Concentrated cocoa supplements are where I'd pause. Just run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Dietrich R, Paglieroni TG, Wun T, et al. Cocoa inhibits platelet activation and function. Am J Clin Nutr 2000;72:30-5. PubMed
  2. Flammer AJ, Hermann F, Sudano I, et al. Dark chocolate improves coronary vasomotion and reduces platelet reactivity. Circulation 2007;116:2376-82. PubMed
  3. Zubair, M. H., Zubair, M. H., Zubair, M. N., Zubair, M. M., Aftab, T., and Asad, F. Augmentation of anti-platelet effects of aspirin. J Pak Med.Assoc. 2011;61(3):304-307.
  4. Rein, D., Paglieroni, T. G., Wun, T., Pearson, D. A., Schmitz, H. H., Gosselin, R., and Keen, C. L. Cocoa inhibits platelet activation and function. Am J Clin Nutr 2000;72(1):30-35. PubMed
  5. Pearson, D. A., Paglieroni, T. G., Rein, D., Wun, T., Schramm, D. D., Wang, J. F., Holt, R. R., Gosselin, R., Schmitz, H. H., and Keen, C. L. The effects of flavanol-rich cocoa and aspirin on ex vivo platelet function. Thromb.Res 5-15-2002;106(4-5):191-1 PubMed
  6. Murphy, K. J., Chronopoulos, A. K., Singh, I., Francis, M. A., Moriarty, H., Pike, M. J., Turner, A. H., Mann, N. J., and Sinclair, A. J. Dietary flavanols and procyanidin oligomers from cocoa (Theobroma cacao) inhibit platelet function. Am J Clin Nutr 2 PubMed
  7. Innes, A. J., Kennedy, G., McLaren, M., Bancroft, A. J., and Belch, J. J. Dark chocolate inhibits platelet aggregation in healthy volunteers. Platelets. 2003;14(5):325-327. PubMed
  8. Hermann, F., Spieker, L. E., Ruschitzka, F., Sudano, I., Hermann, M., Binggeli, C., Luscher, T. F., Riesen, W., Noll, G., and Corti, R. Dark chocolate improves endothelial and platelet function. Heart 2006;92(1):119-120.
  9. Heptinstall, S., May, J., Fox, S., Kwik-Uribe, C., and Zhao, L. Cocoa flavanols and platelet and leukocyte function: recent in vitro and ex vivo studies in healthy adults. J Cardiovasc.Pharmacol. 2006;47 Suppl 2:S197-S205. PubMed
  10. Hamed, M. S., Gambert, S., Bliden, K. P., Bailon, O., Singla, A., Antonino, M. J., Hamed, F., Tantry, U. S., and Gurbel, P. A. Dark chocolate effect on platelet activity, C-reactive protein and lipid profile: a pilot study. South.Med J 2008;101(12):1203- PubMed
  11. Flammer, A. J., Sudano, I., Wolfrum, M., Thomas, R., Enseleit, F., Periat, D., Kaiser, P., Hirt, A., Hermann, M., Serafini, M., Leveques, A., Luscher, T. F., Ruschitzka, F., Noll, G., and Corti, R. Cardiovascular effects of flavanol-rich chocolate in pat
  12. Seecheran NA, Sukha D, Grimaldos K, et al. Effect of cocoa (Theobroma cacao L.) on platelet function testing profiles in patients with coronary artery disease: ECLAIR pilot study. Open Heart 2022;9(2):e002066.

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

Cocoa Also Interacts With Other Medications

Cocoa has 634 moderate, 26 minor 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 634 Minor 26 No known interaction 2,170 (incl. Pentoxifylline)
Taking anything else?

Check Another of Your Medications Against Cocoa

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

Everything else you take

See Every Supplement That Interacts With Pentoxifylline

This page covers Cocoa 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 Cocoa as Part of a Dietary Supplement Product? Check It for Interactions

We hold 844 real supplement products containing Cocoa, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cocoa. Your product may carry other ingredients that interact with Pentoxifylline too, on top of Cocoa — 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 Cocoa 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 Cocoa
Top 25%

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

29 days ago today
Medication Pentoxifylline
Top half

#906 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 Cocoa

What is Cocoa?

Cocoa
  • Heart and blood vessel health
  • High blood pressure
  • High cholesterol
  • Mental focus and mood
  • Skin moisturizing (cocoa butter)

Cocoa is rich in plant compounds called flavanols that may modestly support blood vessel function and blood pressure, but most chocolate products are high in sugar, fat, and calories, which can offset any benefit. Enjoy cocoa as part of a balanced diet, and talk to your pharmacist before using concentrated cocoa supplements, especially if you have heart or blood pressure conditions.

Read the full Cocoa 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 & Cocoa

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

0Major
634Moderate
26Minor
2,169No known interaction
634 Moderate 26 Minor 2,169 No interaction
Moderate

634 interactions

Showing 60 of 634 moderate interactions — see all 634 on the Cocoa page.

Minor

26 interactions

No interaction 2,169 drugs checked — show the list

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

Showing the 60 most looked-up of 2,169 medications checked with no known interaction — see the full Cocoa list.

See the full Cocoa 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
Cocoa 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 Cocoa and Pentoxifylline Together: Common Questions

Can you take Cocoa 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 Cocoa 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 Cocoa?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.