Drug & supplement interaction

Capsicum + Aspirin, Codeine Phosphate, Phenobarbital

Aspirin, Codeine Phosphate, Phenobarbital brand name: Phenaphen.

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

Aspirin, Codeine Phosphate, Phenobarbital falls into 2 drug categories that Capsicum can interact with; the most serious is rated moderate. Theoretically, capsicum may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Capsicum and Aspirin, Codeine Phosphate, Phenobarbital

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Capsicum interacts with whole categories of medication. Aspirin, Codeine Phosphate, Phenobarbital falls into 2 of those categories, so it can interact with Capsicum in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

1 of 2

Why this applies to Aspirin, Codeine Phosphate, Phenobarbital

Aspirin, Codeine Phosphate, Phenobarbital falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Capsicum interacts with.

Theoretically, capsicum may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
In vitro research shows that capsicum might increase the effects of antiplatelet drugs. Also, population research shows that capsicum is associated with an increased risk of self-reported bleeding in patients taking warfarin. However, clinical research shows that taking a single dose of capsaicin (Asian Herbex Ltd.), the active ingredient in capsicum, 400-800 mcg orally in combination with aspirin 500 mg does not decrease platelet aggregation when compared with taking aspirin 500 mg alone. Also, there was no notable effect on measures of platelet aggregation with capsaicin. It is unclear whether capsaicin must be used in more than a single dose to affect platelet aggregation.
Severity Moderate Likelihood Possible Evidence B

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

This combination pill contains aspirin, which thins the blood by blocking platelets from clumping together. The piece worth knowing about with capsicum (chili pepper) is the aspirin part. In theory, capsaicin may add a little to aspirin's blood-thinning action, which could mean easier bruising, nosebleeds, or stomach upset and bleeding. Honestly though, the evidence here is thin. One study found that a single dose of capsaicin alongside aspirin did not change how platelets behaved.

The codeine and phenobarbital parts aren't really the concern with capsicum. Food amounts of chili are very unlikely to matter. If you regularly take concentrated capsicum supplements, just mention it to your pharmacist or doctor so they can keep an eye on any bleeding signs.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Bouraoui A, Brazier JL, Zouaghi H, Rousseau M. Theophylline pharmacokinetics and metabolism in rabbits following single and repeated administration of Capsicum fruit. Eur J Drug Metab Pharmacokinet 1995;20:173-8.
  2. Hogaboam CM, Wallace JL. Inhibition of platelet aggregation by capsaicin. An effect unrelated to actions on sensory afferent neurons. Eur J Pharmacol 1991;202:129-31. PubMed
  3. Wang JP, Hsu MF, Teng CM. Antiplatelet effect of capsaicin. Thromb Res 1984;36:497-507. PubMed
  4. Shalansky S, Lynd L, Richardson K, et al. Risk of warfarin-related bleeding events and supratherapeutic international normalized ratios associated with complementary and alternative medicine: a longitudinal analysis. Pharmacotherapy. 2007;27:1237-47. PubMed
  5. Sandor B, Papp J, Mozsik G, et al. Orally given gastroprotective capsaicin does not modify aspirin-induced platelet aggregation in healthy male volunteers (human phase I examination). Acta Physiol Hung. 2014 Dec;101(4):429-37. PubMed
Moderate

ASPIRIN

2 of 2
Theoretically, taking capsicum with aspirin might reduce the bioavailability of aspirin.
Animal research shows that acute or chronic intake of capsicum pepper reduces oral aspirin bioavailability. This has not been shown 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

This combination pill (Phenaphen) pairs aspirin with codeine and phenobarbital, and the interaction on file is specifically about the aspirin part. The thinking is that capsicum (chili pepper) might lower how much aspirin your body actually absorbs. If less aspirin gets in, you could in theory get a bit less pain and fever relief from it.

Here is the honest part: this has only been seen in animal studies, not in people, so it is very much theoretical. Everyday food amounts of chili almost certainly do not matter. Concentrated capsaicin supplements are less studied. None of this changes how codeine or phenobarbital work. If you take this medicine regularly and use capsicum supplements, just mention it to your pharmacist or doctor so they can keep an eye on how well your pain is controlled.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Cruz L, Castañeda-Hernández G, Navarrete A. Ingestion of chilli pepper (Capsicum annuum) reduces salicylate bioavailability after oral asprin administration in the rat. Can J Physiol Pharmacol.

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

Capsicum Also Interacts With Other Medications

Capsicum has 214 moderate, 24 minor known drug interactions in our database — the Aspirin, Codeine Phosphate, Phenobarbital one above is among them. If you take anything else, check it against the full list below.

Moderate 214 Minor 24 No known interaction 2,592 (incl. Aspirin, Codeine Phosphate, Phenobarbital)
Taking anything else?

Check Another of Your Medications Against Capsicum

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

Everything else you take

See Every Supplement That Interacts With Aspirin, Codeine Phosphate, Phenobarbital

This page covers Capsicum only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Aspirin, Codeine Phosphate, Phenobarbital page lists 352 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Asarabacca (major), Beer (major) and Danshen (major).

By severity: 12 major · 304 moderate · 36 minor.

From our pharmacist’s overview on the Aspirin, Codeine Phosphate, Phenobarbital page

“Alcohol is the entry I would flag first with Phenaphen (aspirin, codeine phosphate, phenobarbital): beer or wine layered onto codeine and phenobarbital can deepen sedation and, at worst, slow breathing. This medication deserves real caution with supplements.”

Reviewed by 2 · Jul 18, 2026

Open the Aspirin, Codeine Phosphate, Phenobarbital interaction page

One more smart check

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

We hold 4,130 real supplement products containing Capsicum, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Capsicum. Your product may carry other ingredients that interact with Aspirin, Codeine Phosphate, Phenobarbital too, on top of Capsicum — 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 Capsicum and Aspirin, Codeine Phosphate, Phenobarbital 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 Capsicum
Top 5%

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

29 days ago today
Medication Aspirin, Codeine Phosphate, Phenobarbital
Top 25%

#494 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 Capsicum

What is Capsicum?

  • Nerve pain (neuropathy)
  • Muscle and joint pain (arthritis)
  • Back pain
  • Digestive support
  • Cluster headache (intranasal)

Capsicum (chili pepper) contains capsaicin, which is best known and best studied as a topical treatment for certain types of pain. Topical capsaicin products are supported by reasonable evidence for some nerve and joint pain, but oral supplements are far less proven. Use it carefully, follow product directions, and talk to your pharmacist or doctor before starting.

Read the full Capsicum monograph & all interactions
Keep checking

Other Drugs & Capsicum

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

0Major
214Moderate
24Minor
2,591No known interaction
214 Moderate 24 Minor 2,591 No interaction
Moderate

214 interactions

Showing 60 of 214 moderate interactions — see all 214 on the Capsicum page.

Minor

24 interactions

No interaction 2,591 drugs checked — show the list

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

Showing the 60 most looked-up of 2,591 medications checked with no known interaction — see the full Capsicum list.

See the full Capsicum interactions page
See every supplement checked against Aspirin, Codeine Phosphate, Phenobarbital, 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
Capsicum monograph › Uses, safety, and every drug interaction in one place Aspirin, Codeine Phosphate, Phenobarbital supplement interactions › Every supplement checked against Aspirin, Codeine Phosphate, Phenobarbital, 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 Capsicum and Aspirin, Codeine Phosphate, Phenobarbital Together: Common Questions

Can you take Capsicum with Aspirin, Codeine Phosphate, Phenobarbital?
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.
Why are there 2 interactions listed for Capsicum and Aspirin, Codeine Phosphate, Phenobarbital?
Aspirin, Codeine Phosphate, Phenobarbital belongs to more than one drug category, and Capsicum interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Capsicum and Aspirin, Codeine Phosphate, Phenobarbital 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

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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.