Consumer information: Cannabis
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Organization: Health Canada
Date published: 2025-04-10
The official version of this document, which has been incorporated by reference as part of the Cannabis Regulations, is the PDF version available for download at right. The document must be printed double-sided (one side English, one side French), in colour, full size, on 8.5 by 14 inch white paper. Questions concerning the use of this document can be directed to: cannabis@canada.ca.
Overall, the evidence for the safety and efficacy of cannabis for medical purposes is limited or unknown. Follow the instructions from your health care practitioner when using cannabis for medical purposes.
Cannabinoids. Cannabis and cannabis products contain cannabinoids that affect the brain and body.
The two most common cannabinoids are THC and CBD. THC causes the intoxicating and impairing effects of cannabis and has addictive potential. CBD is not intoxicating nor addictive but still has effects.
| Ways of using cannabis | When effects could begin | How long effects could last | Potential benefits and risks |
|---|---|---|---|
| Ingesting (eating, drinking, under tongue) |
30 minutes to 2 hours |
4–8 hoursFootnote * |
|
| Inhaling (smoking, vaping) |
Seconds to minutes | 2–4 hoursFootnote * |
|
| Topically (applying to skin) |
N/A | N/A |
|
|
|||
Side effects. Everyone's response to cannabis differs and can vary from one time to the next. Immediate effects can include euphoria ("high"), dizziness/feeling faint, increased heart rate, changes in thinking, anxiety, panic, paranoia, increased appetite, impaired memory and attention, dry mouth, red eyes, and drowsiness.
Serious side effects can include, but are not limited to, psychotic symptoms involving extreme confusion, severe anxiety, paranoia, and hallucinations. If you overconsume and feel unwell, call 1-844-POISON-X (1-800-463-5060 in Quebec), call 9-1-1, or go to your nearest hospital.
Reporting side effects. You can report side effects to your health care practitioner, the product manufacturer, or directly to Health Canada by calling 1-866-234-2345 or filling a side effect report online.
Reduce and manage risks
- Check and understand the label. Make sure the product your health care practitioner recommended is the one you received. CBD products can contain some amount of THC, which can cause side effects; carefully read the label before consuming any cannabis. If in doubt, or you have any questions, contact your health care practitioner.
- Tell your health care practitioner about use of other drugs or health products. Cannabis can interact with other drugs and substances. This can cause side effects, some of which may be serious. It is important to tell your health care practitioner if you are taking or changing prescription or non-prescription drugs or natural health products. Take caution when combining cannabis with other drugs and health products and avoid combining with intoxicating substances such as alcohol.
- Monitor dosing and effects. Follow the recommended dosing by your health care practitioner. Monitor your treatment and follow-up with your health care practitioner to adjust your treatment plans if needed.
- Store cannabis safely. Edibles can poison children and be life-threatening. Keep out of sight and reach of children and pets. Store all cannabis in its original child-resistant packaging.
- Do not drive under the influence of cannabis. It puts your life and other people's lives at risk.
For more information on cannabis for medical purposes, visit Canada.ca/cannabis.
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