Published on October 28, 2026
Cannabis, Medication and Your Liver
Learn how cannabis may interact with medications, how this can impact the liver, and why a conversation with a pharmacist or doctor can be important. This article provides general information and does not replace advice from a healthcare professional. Always speak to a medical professional if you have questions about cannabis consumption and medications.
Why this matters
If you take medication and consume cannabis, it's reasonable to wonder how the two might interact. Concern about combining cannabis with prescription and over-the-counter medication is common among older adults, and people often say they are simply not aware of what to watch for.
Even though cannabis and a medication may not interact directly with each other, cannabis can slow your liver’s ability to process certain medications.
Key takeaways
- Your liver does most of the work of processing cannabis.
- Cannabis can slow down the same liver system that processes many common medications, so medications may build up or clear your body more slowly.
- People who take several medications, and people with liver conditions, have more reason to check with a healthcare professional.
- Your pharmacist or doctor is the best person to consult.
- When buying cannabis, look for Authorized Cannabis Stores to ensure you know what you’re consuming.
How your body processes cannabis
When you ingest cannabis in an edible, capsule or oil, most of it passes through your liver before reaching the rest of your body, lengthening the amount of time it takes to feel the effects. Your liver then clears the cannabis out of your system over time. Smoking or vaping works differently: the inhaled cannabis is absorbed through your lungs, largely skipping that first pass through the liver, and taking effect faster. The liver plays a smaller role in processing inhaled cannabis than ingested cannabis, but it’s still working to clear the cannabis from your body.
How cannabis can affect the way medications are processed
Which medications are affected by cannabis use? This is where a pharmacist or healthcare provider comes in. Interactions between cannabis and medication depend on the specific medication, the dose and the individual. As a general illustration- and not a complete list- cannabis may interact with certain blood thinners, antidepressants, anti-seizure medications, cholesterol medications and sedatives. Your pharmacist or doctor can help you understand whether your cannabis consumption may be relevant to your medications and individual circumstances.
The most important thing to do
Before combining cannabis with any medication, ask your pharmacist or doctor. They can look at your specific medications and tell you whether anything needs attention.
Cannabis and your liver
Research on the relationship between cannabis and liver health is still evolving. Factors such as the type and amount of cannabinoids consumed, frequency of use, underlying health conditions and use of other medications may impact individual experiences.
While some studies have identified that high doses of CBD may cause temporary changes in liver enzyme levels, which can be a sign that the liver is working harder, there is still much to learn about the effects of cannabinoids in cannabis products. If you regularly use medications, consume cannabis products containing higher amounts of CBD, or have liver-related health concerns, consider speaking with your pharmacist or healthcare provider.
Why this matters more as we age
As people age, the liver’s processing enzymes generally become a little less active. Older people are more likely to take several medications at once. Together, those changes mean that the interactions between cannabis and drug interaction can be more impactful than they would be for a younger person. That doesn’t necessarily mean that cannabis is off-limits, but it’s a good reason to ask questions and go carefully.
Ways to reduce your risk
- Start low, go slow, especially when trying a new product or format or returning to cannabis after a break.
- Purchase legal cannabis from an Authorized Cannabis Store or OCS.ca to help ensure you are getting products that are regulated, tested and accurately labelled.
- Keep an up-to-date list of the cannabis, prescription medications, over-the-counter medications and supplements you take.
- Read the product label to understand how much THC and CBD the product contains.
- Ask your pharmacist or doctor before combining cannabis with any medication.
This article covers general information on how cannabis and medications relate. It is not medical advice and does not replace guidance from a healthcare provider. Always discuss your specific situation with your healthcare provider before consuming cannabis
Additional resources
These resources can help you learn more about cannabis, medications and liver health. They are provided for general information only and do not replace advice from a pharmacist, doctor or other healthcare provider.
- Health Canada: Consumer information about cannabis, including responsible use, health effects and product safety.
- Canadian Centre on Substance Use and Addiction: Plain-language resources on cannabis use, including information for older adults.
- Cannabis Made Clear: Related OCS articles with practical information about cannabis products, effects and responsible consumption.
- Healthcare professional or pharmacist: The best source for questions about your own medications, cannabis use, health conditions and potential interactions.
