Cannabis Made Clear

Mixing Cannabis With Alcohol and Other Substances: What You Need to Know

Combining cannabis with other substances can have adverse health effects. Find out what the risks are associated with mixing cannabis with another substance and how to best mitigate them.

Open faced hands holding some pills

Mixing cannabis with alcohol, tobacco or prescription medication can produce a host of potentially negative or even harmful effects — particularly for occasional users, says Dr. Daniel Bear, a drugs policy researcher and Humber College professor.

Read on to learn how cannabis interacts with other substances and get tips on how to minimize your risk by using some harm reduction strategies.

Mixing cannabis and alcohol

When it comes to mixing cannabis with alcohol, Dr. Bear’s concerns are twofold: A person who chooses to use a cannabis product after having a few drinks will likely feel much more intoxicated for a longer period, since alcohol increases THC levels in the blood.

Tip: Avoid mixing cannabis with psychoactive substances.

Mixing cannabis with other psychoactive substances including illicit drugs can produce unpredictable effects and can lead to greening out, passing out, vomiting and so on.

Similarly, when someone uses cannabis before alcohol, it can become harder to judge their level of intoxication — especially when using a digestible product like an edible or capsule, which takes longer to kick in. Both less-experienced cannabis users, as well as those who frequently use alcohol and cannabis at the same time, may encounter some adverse effects.

And as Dr. Bear explains, the result of cannabis plus alcohol is not usually a matter of one plus one. “It’s not simply an additive situation but can be more of a multiplier. And it’s different for different people, because all of our endocannabinoid systems are different,” says Dr. Bear. “It’s super easy to get caught off guard.”

In short, there is a significant risk of experiencing undesirable and unpredictable effects when mixing the two. An individual’s judgment may also become impaired, and risks from combining the two substances are greater when it comes to impaired driving.

Mixing cannabis and tobacco

According to the Canadian Cannabis Survey 2022, Canadians view smoking tobacco or e-cigarettes as riskier than drinking alcohol or consuming cannabis. Based on research, the growth of cannabis use in Canada could introduce people who don’t usually smoke cigarettes to nicotine.

Tip: Stick to one substance.

Combining cannabis with alcohol or tobacco can intensify or alter your high unpredictably. Mixing substances can also increase potential health harms as well as the likelihood that you’ll have a negative experience.

Legacy cannabis smokers may also want to consider retiring spliffs and blunts, which mix cannabis and tobacco. There is research to support that people who mix cannabis and tobacco in their blunts “may be at an increased risk of tobacco-related illnesses, as cannabis smokers typically take longer and deeper inhalations, exposing themselves to more tar.” Also, using cannabis with tobacco can increase the risk for dependence on these substances more than smoking either one alone.

Mixing cannabis and prescription medication

Cannabis may have contra-indications with medication you’re taking and could impact the medication’s effectiveness, says Dr. Bear. For instance, he points out that cannabis can lower blood pressure and increase heart rate — two physiological responses to cannabis that can have negative effects on a person’s health. According to the Canadian Centre on Substance Use and Addiction (CCSA), cannabis can interact with a wide variety of medication types, including drugs prescribed for pain, seizures, depression, anxiety, allergies, ADHD, HIV and AIDS, insomnia and heartburn, among others.

Talk to a medical professional about possible interactions and adverse effects.


Harm Reduction Tips

Fortunately, there are solid harm reduction approaches to rely on when consuming cannabis.

Start low and go slow

Consume a small amount and wait a bit to see how it feels, particularly in a social setting where you may not be aware of a joint or edible’s THC potency. The best way to measure your dose is to go slow. This principle applies whether you’re also drinking or not.

Be mindful of product type

Remember that edibles usually take 60 to 90 minutes to kick in, whereas smoking cannabis has a more immediate effect. The “start low and go slow” rule is particularly important, since you may have a harder time adjusting your dose with edibles. Drinking in the time between consuming an edible and it taking effect can suddenly make you feel more intoxicated than you may like.

Set and setting

Consider how you’re feeling (your mindset) and if the place you’re consuming feels safe and comfortable. If you’ve had too much, do you feel like you can safely sleep it off? Will someone you trust check on you if you’re not feeling well?


Avoid mixing cannabis and consuming alcohol if you’re unfamiliar with how it will affect you. Depending on your metabolism, you may need to wait several hours between consuming alcohol and consuming cannabis to avoid or minimize co-use interactions.

Pick one

If you’re planning on consuming cannabis, consider sticking to one substance to mitigate any unwanted or unexpected effects. The same applies to all other recreational drugs; it’s best to stick to one, so you can have as enjoyable — and as predictable — an experience as possible.

Choose a safe ride option

Mixing can elevate and prolong or increase intoxication, even if you don’t feel high or drunk. As well, because the effects of co-substance use are unpredictable and negative effects can be delayed, these effects could hit you while you’re behind the wheel. The safest route home is the one where either you get a ride home from a sober driver or you are 100% sober before getting into the driver’s seat.

Risk Factors for Simultaneous Use of Alcohol and Cannabis
Public Health Ontario 
7 Things You Need to Know about Edible Cannabis
Canadian Centre on Substance Use and Addiction
Co-use and Mixing Tobacco With Cannabis Among Ontario Adults
National Library of Medicine
Cannabis and Other Substances
Canadian Centre on Substance Use and Addiction
Why Do Some
People Choose to
Consume Cannabis
While Others Do
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Consume Cannabis While
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Syndrome (CHS)?
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Hyperemesis Syndrome (CHS)?