Drug & supplement interaction

Carrageenan + Cilostazol

Cilostazol brand name: Pletal.

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

Carrageenan has a moderate interaction with Cilostazol. Theoretically, carrageenan may increase the risk of bleeding in patients taking anticoagulant or antiplatelet drugs.

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

Carrageenan and Cilostazol

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

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

Why this applies to Cilostazol

Cilostazol falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Carrageenan interacts with.

Theoretically, carrageenan may increase the risk of bleeding in patients taking anticoagulant or antiplatelet drugs.
Laboratory research suggests that carrageenan has anticoagulant effects. However, 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 simple version: cilostazol (Pletal) already works to keep your platelets from clumping, which is how it improves blood flow in your legs. Lab studies hint that carrageenan, the seaweed-based thickener, might have a mild blood-thinning effect of its own. On paper, stacking the two could nudge your bleeding risk up a little, showing up as easy bruising, nosebleeds, bleeding gums, or cuts that take longer to stop.

The key thing to know is that this is purely theoretical. It's only been seen in test-tube research, never reported in actual people, and the tiny amounts of carrageenan in foods like ice cream or deli meats are very unlikely to matter. A concentrated supplement is a different story, so check with your pharmacist or doctor before adding one.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Fetrow CW, Avila JR. Professional's Handbook of Complementary & Alternative Medicines. 1st ed. Springhouse, PA: Springhouse Corp., 1999.

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

Carrageenan Also Interacts With Other Medications

Carrageenan has 121 moderate known drug interactions in our database — the Cilostazol 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. Cilostazol)
Taking anything else?

Check Another of Your Medications Against Carrageenan

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

From our Q&A

Questions About Carrageenan or Cilostazol

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

This page covers Carrageenan only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cilostazol page lists 286 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Danshen (major), Grapefruit (major), Piracetam (major) and St. John's Wort (major).

By severity: 5 major · 240 moderate · 41 minor.

Open the Cilostazol interaction page

One more smart check

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

We hold 31 real supplement products containing Carrageenan, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Carrageenan. Your product may carry other ingredients that interact with Cilostazol too, on top of Carrageenan — 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 Carrageenan and Cilostazol 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 Carrageenan
Steady interest

#1,172 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Cilostazol
Steady interest

#1,624 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 Carrageenan

What is Carrageenan?

  • Food thickener and stabilizer
  • Digestive complaints (traditional use)
  • Cough and sore throat (traditional use)
  • Laxative or bowel-related uses
  • Antiviral (laboratory interest)

Carrageenan is a fiber-like substance taken from red seaweed and is mostly used as a thickener and gelling agent in foods. There is little solid human evidence supporting it as a health supplement, and some forms (especially degraded carrageenan) have raised digestive and inflammation concerns, so it should not be relied on to treat any condition.

Read the full Carrageenan monograph & all interactions
Medication

About Cilostazol

What Is Cilostazol Used For?

Brand name: Pletal

Cilostazol tablets are approved to reduce the symptoms of intermittent claudication (cramping leg pain that comes on during walking due to reduced blood flow in the arteries). The goal is to help you walk farther before pain forces you to stop.

See full Cilostazol drug information
Keep checking

Other Drugs & Carrageenan

Browse every other medication we’ve checked against Carrageenan — 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 Carrageenan page.

No interaction 2,708 drugs checked — show the list

We also checked Carrageenan 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 Carrageenan list.

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

Can you take Carrageenan with Cilostazol?
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 Carrageenan and Cilostazol 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 Cilostazol and Carrageenan?

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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.