Drug & supplement interaction

Cannabis + Acetaminophen, Aspirin

Acetaminophen, Aspirin brand name: Gemnisyn.

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

Acetaminophen, Aspirin falls into 2 drug categories that Cannabis can interact with; the most serious is rated moderate. Theoretically, cannabis might increase the risk of bleeding when used concomitantly with anticoagulant/antiplatelet drugs.

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

Cannabis and Acetaminophen, Aspirin

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

Why Are There 2 Interactions?

Cannabis interacts with whole categories of medication. Acetaminophen, Aspirin falls into 2 of those categories, so it can interact with Cannabis 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 Acetaminophen, Aspirin

Acetaminophen, Aspirin falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Cannabis interacts with.

Theoretically, cannabis might increase the risk of bleeding when used concomitantly with anticoagulant/antiplatelet drugs.
In vitro research shows that the cannabis constituents delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) inhibit 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

Gemnisyn pairs aspirin with acetaminophen, and it's the aspirin part that matters here. Aspirin already thins your blood a bit by keeping platelets from clumping together. The concern is that cannabis may do something similar. In lab (test tube) studies, the THC and CBD in cannabis also slowed platelets from sticking. Stack those two together and, in theory, you could bruise or bleed a little more easily, things like nosebleeds, bleeding gums, or a cut that's slow to stop.

I want to be honest about how soft this evidence is. It comes from lab studies only, not real patients, so we don't truly know if it plays out in people. Still, if you use cannabis regularly while taking Gemnisyn, it's worth a quick chat with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Levy, R., Schurr, A., Nathan, I., Dvilanski, A., and Livne, A. Impairment of ADP-induced platelet aggregation by hashish components. Thromb.Haemost. 12-31-1976;36(3):634-640. DOI
  2. Formukong, E. A., Evans, A. T., and Evans, F. J. The inhibitory effects of cannabinoids, the active constituents of Cannabis sativa L. on human and rabbit platelet aggregation. J.Pharm.Pharmacol. 1989;41(10):705-709.
Moderate

CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES

2 of 2

Acetaminophen, Aspirin also falls under CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES.

Theoretically, cannabis might decrease the levels and clinical effects of CYP2E1 substrates.
In vitro research shows that cannabis can induce the activity of CYP2E1, which might increase the metabolism of CYP2E1 substrates.
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 thing to keep in mind with Gemnisyn (the acetaminophen and aspirin combo) and cannabis. The acetaminophen part is partly handled by a liver enzyme called CYP2E1. Lab studies suggest cannabis might speed that enzyme up, which could break acetaminophen down a little faster. In theory that might slightly lessen its pain or fever relief.

I want to be honest, though: this is based only on test-tube research, not real people, so we don't truly know if it matters in everyday life. One thing worth a brief mention is that the CYP2E1 pathway can also create a liver-stressing byproduct of acetaminophen, so it's smart not to exceed the recommended dose. If you use both regularly, just check in with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sheweita, S. A. Narcotic drugs change the expression of cytochrome P450 2E1 and 2C6 and other activities of carcinogen-metabolizing enzymes in the liver of male mice. Toxicology 9-30-2003;191(2-3):133-142. PubMed

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

Cannabis Also Interacts With Other Medications

Cannabis has 2 major, 1,108 moderate, 25 minor known drug interactions in our database — the Acetaminophen, Aspirin one above is among them. If you take anything else, check it against the full list below.

Major 2 Moderate 1,108 Minor 25 No known interaction 1,695 (incl. Acetaminophen, Aspirin)
Taking anything else?

Check Another of Your Medications Against Cannabis

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

From our Q&A

Questions About Cannabis or Acetaminophen, Aspirin

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

This page covers Cannabis only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Aspirin page lists 321 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Danshen (major) and Piracetam (major).

By severity: 7 major · 270 moderate · 44 minor.

From our pharmacist’s overview on the Acetaminophen, Aspirin page

“Acetaminophen with aspirin (Gemnisyn) is the kind of pain reliever people take without a second thought, which is exactly why its interaction list deserves genuine care. More than 200 of the 321 ingredients on file thin the blood in some way, and layered on top of aspirin that means a higher chance of bleeding, especially in the stomach.”

Reviewed by 2 · Jul 18, 2026

Open the Acetaminophen, Aspirin interaction page

One more smart check

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

We hold 21 real supplement products containing Cannabis, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cannabis. Your product may carry other ingredients that interact with Acetaminophen, Aspirin too, on top of Cannabis — 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 Cannabis and Acetaminophen, Aspirin 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 Cannabis
Top 25%

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

29 days ago today
Medication Acetaminophen, Aspirin
Top 25%

#334 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 Cannabis

What is Cannabis?

Cannabis
  • Chronic pain
  • Nausea and vomiting from chemotherapy
  • Muscle spasticity (e.g., multiple sclerosis)
  • Anxiety and stress
  • Sleep problems
  • Appetite stimulation

Cannabis contains many active compounds, mainly THC (which causes a 'high') and CBD (which does not). Some uses, such as chemotherapy-related nausea, certain seizure disorders, and muscle spasticity, have meaningful evidence, while many other popular uses are not well proven. It can cause real side effects and impairment, so talk to your doctor or pharmacist and follow your local laws before using it.

Read the full Cannabis monograph & all interactions
Keep checking

Other Drugs & Cannabis

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

2Major
1,108Moderate
25Minor
1,694No known interaction
2 Major 1,108 Moderate 25 Minor 1,694 No interaction
Major

2 interactions

Moderate

1,108 interactions

Showing 60 of 1,108 moderate interactions — see all 1,108 on the Cannabis page.

Minor

25 interactions

No interaction 1,694 drugs checked — show the list

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

Showing the 60 most looked-up of 1,694 medications checked with no known interaction — see the full Cannabis list.

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

Can you take Cannabis with Acetaminophen, Aspirin?
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 Cannabis and Acetaminophen, Aspirin?
Acetaminophen, Aspirin belongs to more than one drug category, and Cannabis 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 Cannabis and Acetaminophen, Aspirin 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 Acetaminophen, Aspirin and Cannabis?

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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.