CBD and Aspirin (e.g. Bayer Aspirin, Ecotrin, ASA, Thomapyrin)
David ReichUpdated:Key points at a glance:
CBD may influence liver enzymes such as CYP2C9, CYP3A4 and UGT. Aspirin affects blood platelets. Used together, there may be an increased tendency to bleed. Extra caution is advisable in cases of gastrointestinal complaints, older age, use of additional anticoagulant or antiplatelet medicines, and before surgical procedures. Leave a gap of two to three hours between taking CBD and aspirin. Begin with a low CBD dose. Watch for signs such as unusual bruising or very dark (black) stools. Seek advice from a doctor or pharmacist before using them together.
Cannabidiol (CBD) has come into greater focus in recent years – many people report positive experiences, for example in relation to general wellbeing and relaxation. Aspirin, also known as acetylsalicylic acid (ASA), has been used for decades as a pain reliever and to inhibit blood platelets. But what should be considered when both are taken together? This article summarises current knowledge on CBD and aspirin (for example Bayer Aspirin, Ecotrin, ASA, Thomapyrin), practical tips and warning signs in a compact and accessible way.
- CBD can inhibit enzymes involved in the metabolism of medicines (including CYP2C9/CYP3A4, UGT).
- Aspirin inhibits blood platelets; when taken together with CBD, the theoretical risk of bleeding may increase.
- Particular caution is advisable in people with stomach or bowel problems, those taking other blood-thinning medicines, older adults or before surgery.
- A gap of 2–3 hours between doses may be sensible; start with a low CBD dose.
- Discuss the combination with a doctor or pharmacist in advance and watch for warning signs such as bruising or black stools.
How do CBD and aspirin work in the body?
CBD: effects, metabolism and liver enzymes
CBD is a naturally occurring component of the hemp plant. It interacts with the endocannabinoid system (ECS), which is involved in regulating mood, sleep, inflammatory processes and the perception of pain. CBD is taken, for example, as CBD drops and oils.
After intake, CBD is mainly metabolised by enzymes of the cytochrome P450 family (CYP2C9, CYP2C19, CYP3A4) and by UGT enzymes (for example UGT1A9, UGT2B7) in the liver. Laboratory and clinical data indicate that CBD can inhibit these liver enzymes – this can increase exposure to certain prescription medicines that are also metabolised via CYP3A4, CYP2C9 or UGT pathways. Overall, the amount of data on CBD drug interaction is limited; the mechanisms are considered plausible, but larger clinical studies are lacking.
CBD acts via the ECS and is broken down by liver enzymes (CYP and UGT), which it can partly inhibit. Because of this effect on CBD metabolism, interactions with other medicines are plausible.
Aspirin (ASA): effects and metabolism
Aspirin (acetylsalicylic acid) is a non-steroidal anti-inflammatory drug (NSAID). It affects prostaglandins through acetylation and thus irreversible inhibition of COX‑1 in platelets (platelet-inhibiting effect) and COX enzymes in tissues (analgesic/antipyretic). After ingestion, ASA is rapidly hydrolysed by carboxylesterases to salicylic acid.
Salicylic acid is mainly broken down via conjugation: glucuronidation (UGT) and glycine conjugation (to salicyluric acid); a small proportion is oxidatively metabolised, including via CYP2C9. The platelet-inhibiting effect lasts until the affected platelets are broken down (irreversible). Official information is available, for example, from MedlinePlus: Aspirin.
Aspirin has a sustained inhibitory effect on blood platelets. It is rapidly converted to salicylic acid and excreted mainly via glucuronidation and glycine conjugation, with a smaller contribution from CYP2C9.
Can CBD and aspirin interact?
CBD liver enzymes (CYP3A4, CYP2C9, UGT) and theoretical effects on aspirin
CBD can inhibit CYP2C9, CYP2C19, CYP3A4 and UGT enzymes (for example UGT1A9/UGT2B7). Because salicylic acid is conjugated via UGT and, to a small extent, oxidised via CYP2C9, increased exposure to salicylate is theoretically possible when CBD and aspirin are taken together. This type of CBD drug interaction via CYP and UGT pathways has not yet been conclusively demonstrated in clinical settings for aspirin; in view of the plausible mechanisms, however, a cautious approach is advisable – particularly where there are additional factors that may increase bleeding risk.
Additive bleeding risk when combining CBD and aspirin
Aspirin affects platelets in a consistent and predictable way. For CBD, there are in vitro findings and case reports suggesting possible effects on platelet function. The combination may therefore potentially increase the tendency to bleed, especially if other risk factors are present (for example additional blood-thinning medicines or pre-existing gastrointestinal problems).
CBD can inhibit metabolic enzymes that process salicylic acid and may also influence platelets. Together with aspirin’s antiplatelet effect, this makes an increased bleeding tendency a plausible, though not firmly established, clinical risk.
If you are considering using CBD together with aspirin, it is sensible to proceed cautiously and in a structured way: start with a low CBD dose, consider separating the doses in time, watch for warning signs and seek medical advice.
Who should be particularly cautious with CBD and aspirin?
- A history of stomach or intestinal ulcers or gastrointestinal bleeding
- Concurrent use of other anticoagulants/antiplatelet agents (for example warfarin, apixaban, clopidogrel), SSRI/SNRI antidepressants or high-dose omega‑3 fatty acids
- Older age, reduced kidney or liver function, regular alcohol consumption
- Planned operations or dental procedures
If any of these points apply to you, medical advice before combining CBD and aspirin is particularly important.
CBD and aspirin: comparison at a glance
| Parameter | CBD | Aspirin (ASA) |
|---|---|---|
| Mode of action | Modulation of the endocannabinoid system | COX inhibitor; irreversible inhibition of platelets |
| Metabolism | CYP2C9/2C19/3A4; UGT (for example UGT1A9/UGT2B7) | Hydrolysis to salicylic acid; UGT/glycine conjugation; minor CYP2C9 component |
| Main areas of use | General wellbeing/relaxation; wide range of applications | Pain/fever; cardiovascular secondary prevention |
| Main risks | Tiredness, gastrointestinal discomfort, interactions with other medicines | Gastrointestinal irritation/bleeding |
| Potential interaction | Increased salicylate exposure via CYP/UGT inhibition and additive tendency to bleed (theoretical/plausible) | |
Practical guide: using CBD safely if you take aspirin
- Compile a list of all medicines (including over-the-counter and herbal products) and have it checked by a doctor or pharmacist for possible CBD drug interaction.
- Start with a low CBD dose and consider separating the intake of CBD and aspirin by 2–3 hours.
- Monitor carefully for 1–2 weeks: skin (bruising), nosebleeds, bleeding gums, stomach discomfort, stool/urine.
- If anything unusual occurs: pause intake and consult a doctor.
- Unexplained bruising, nosebleeds, bleeding gums
- Black stools, blood in the urine, persistent stomach pain
- Dizziness, marked tiredness, ringing in the ears
If these signs occur: pause intake and seek medical assessment.
Tip: Keep a brief intake diary (date, dose, time, observations). This makes it easier for healthcare professionals to assess the situation.If you combine CBD and aspirin, use a low CBD dose, separate doses in time where possible, monitor for bleeding signs and involve a healthcare professional – especially if you use other prescription medicines.
Side effects and warning signs
CBD side effects and interactions
CBD is generally considered to be well tolerated. Possible side effects include tiredness, dizziness, dry mouth, changes in appetite and occasional gastrointestinal discomfort. The likelihood may increase with higher doses and individual sensitivity.
Because CBD can inhibit liver enzymes such as CYP3A4 and CYP2C9, interactions with other prescription medicines are possible. Start low, increase slowly and check for potential interactions..
Aspirin side effects
Common side effects include stomach discomfort (nausea, heartburn), irritation through to ulcers or bleeding – particularly with long-term use or higher doses. Allergic reactions (breathing difficulties, skin rash, swelling) may occur in some individuals. Further general information is available, for example, from MedlinePlus: Aspirin.
Seek medical advice promptly if you experience marked stomach pain, black stools, blood in urine, breathing difficulties, severe dizziness or persistent unusual tiredness while taking CBD and aspirin together.
CBD interaction check for aspirin and other medicines
With our tool, you can look up commonly reported interactions between CBD and frequently used medicines. It provides an initial indication but does not replace individual medical advice or a personalised assessment of CBD and prescription medicines.
💊 Medication Finder
We have analysed the interactions between CBD and 140 medications und Medikamentenarten analysiert. You can view the full overview here or use the search below to find your specific medication.
Conclusion and next steps
Many people find that CBD fits well into their daily routine and that they tolerate it well. When combining CBD with aspirin, it is important to act prudently: be aware of potential CBD drug interaction mechanisms (for example CYP3A4, CYP2C9 and UGT inhibition), watch for warning signs, consider separating doses in time and coordinate your regimen with a doctor or pharmacist. This way, CBD can be used with a focus on safety and your individual situation.
Disclaimer: This article is for information purposes only and does not replace medical advice. Do not change medicines or dosages without consulting your doctor. No claims are made regarding the treatment or cure of illnesses.