Minimizing risks and harms of cannabis

The safest choice is no cannabis use at all. If you choose to use cannabis, you should understand the risks. For more information on how you can reduce your risk of experiencing harms, see Canada's Lower-Risk Cannabis Use Guidelines. 

Legal edible products can have up to 10 mg THC per package. Start with 2.5 mg THC or less.

Start Low. Go Slow!

After you use, wait to feel the effects.

  • Effects from smoking, vaping or dabbing cannabis can,
    • be felt within seconds to minutes
    • take up to 30 minutes to feel the full effects
    • last up to six hours or longer
    • Effects from edible cannabis products can,
    • be felt as quickly as 30 minutes to two hours
    • take up to four hours to feel the full effects
    • last up to 12 hours
    • some residual effects can last up to 24 hours

Mixing with other substances 

If you choose to consume cannabis in any form, avoid combining it with nicotine, alcohol, drugs, medications and other products as it may negatively affect your health. Some key known effects and risks associated with combining cannabis with other substances include:

Cannabis and alcohol

Mixing alcohol and cannabis increases impairment, which can lead to risky choices.

  • When cannabis is used with alcohol, it increases the strength of THC which can lead to adverse side effects.
  • Simultaneous use of alcohol and cannabis are associated with increased intoxication and impairment.
  • Mixing increases the risk of injury, falls or death.

Learn more about the effects of cannabis and alcohol. 
Cannabis and tobacco
  • Cannabis can increase your rate of smoking tobacco.
  • Smoking tobacco can increase your rate of smoking cannabis.
  • Using both cannabis and tobacco simultaneously can result in greater risk for addiction and health risks like cancer, cardiovascular and respiratory disease.

Learn more about the effects of cannabis and tobacco. 

Cannabis and medications
  • Mixing cannabis and medications may alter the effect of prescription and non-prescription drugs.
  • Talk to your healthcare provider or pharmacists about ways to reduce your risks.

Learn more about the effects of cannabis and medications. 

Driving and cannabis use

Cannabis use alters the skills you need to drive such as quick thinking, decision-making, reaction time, and concentration. Never drive impaired or get in a car with an impaired driver.

Plan a safe ride with a friend, use public transportation (Grand River Transit), taxi, or a ride sharing service (i.e. Lyft, Uber). 

Learn more about the Myths and Facts of Impaired Driving from the Ministry of Transportation. Learn more about the dangers of driving high from Health Canada.

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