Drug & supplement interaction

Cocoa + Fondaparinux

Fondaparinux brand name: Arixtra.

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

Cocoa has a moderate interaction with Fondaparinux. 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?
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Interaction report

Cocoa and Fondaparinux

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

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

Why this applies to Fondaparinux

Fondaparinux 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 with cocoa and your fondaparinux (Arixtra). Fondaparinux already lowers your blood's ability to clot by blocking a clotting factor called factor Xa. Cocoa's flavanols can make platelets (the cells that help form clots) a little stickier in reverse, meaning they clump less easily. Stack those two together and, in theory, you could bruise or bleed a bit more easily.

The good news is this is a theoretical concern based on how these compounds work, not strong proof from real-world studies. A normal cup of cocoa or a square of chocolate is very unlikely to matter. Concentrated cocoa supplements are where I'd be more cautious. Watch for unusual bruising, nosebleeds, or bleeding gums, and check with your pharmacist or doctor before starting any cocoa supplement.

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 Fondaparinux 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. Fondaparinux)
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 Fondaparinux

This page covers Cocoa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fondaparinux page lists 202 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Danshen (major), Piracetam (major), Aconite (moderate), Allspice (moderate) and Aloe (moderate).

By severity: 2 major · 183 moderate · 17 minor.

From our pharmacist’s overview on the Fondaparinux page

“Most people on fondaparinux (Arixtra) are recovering from surgery or treating a blood clot, exactly the moment supplements for circulation and recovery come out of the cabinet. This pairing deserves real care, because nearly all 202 ingredients on this list share one problem: they thin the blood a little on their own, so adding them to…”

Reviewed by 2 · Jul 18, 2026

Open the Fondaparinux 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 Fondaparinux 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 Fondaparinux 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%

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

29 days ago today
Medication Fondaparinux
Top half

#915 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 Fondaparinux Injection

What Is Fondaparinux Injection Used For?

Brand name: Arixtra

Fondaparinux sodium injection is used to prevent deep vein thrombosis (DVT) — blood clots that form in the legs — in adults who are having hip fracture surgery, hip replacement surgery, knee replacement surgery, or abdominal surgery. For hip fracture patients, an extended course of prevention is recommended after the initial treatment period.

It is also used to treat an existing DVT or acute pulmonary embolism (PE — a clot in the lungs) in adults, always given alongside warfarin sodium until warfarin reaches a therapeutic level. In pediatric patients aged 1 year and older who weigh at least 10 kg, fondaparinux sodium injection is approved for the treatment of venous thromboembolism (VTE — blood clots in the veins).

See full Fondaparinux Injection 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 Fondaparinux, 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 Fondaparinux supplement interactions › Every supplement checked against Fondaparinux, ranked by severity Fondaparinux Injection 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 Fondaparinux Together: Common Questions

Can you take Cocoa with Fondaparinux?
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 Fondaparinux 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 Fondaparinux and Cocoa?

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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.