Cannabis use can cause adverse effects. Adverse effects can include rapid heart rate, dizziness, varying levels of anxiety, disorganized thoughts, memory loss, nausea, or vomiting. Serious adverse effects can also include psychotic episodes (abnormal behaviour, hallucinations, loss of touch with reality, and delusions), and seizures.
Disclaimer: This information should not be considered legal or medical advice.
Consumers, patients and healthcare practitioners are encouraged to report side effects (adverse reactions) from cannabis products to the producer of the product. Side effects may also be reported to Health Canada’s Canada Vigilance Program.
© Her Majesty the Queen in Right of Canada, 2019 Cat.: H14-295/2018E-PDF
Cannabis can be consumed in different ways.
Two common ways are inhalation (smoking or vaping) and ingestion (eating or drinking). Each way carries different health and safety risks.
Everyone’s response to cannabis is different, depending on sex, age, any pre-existing medical conditions, experience with cannabis, frequency of use, THC and CBD content, and consumption of food, alcohol, other drugs or health products. Everyone’s response to cannabis can also differ from one time to the next.
THC causes the intoxicating effects (or “high”) and the impairing effects, but it can also cause anxiety and other unpleasant and adverse effects. CBD is not intoxicating and may reduce some of the effects of THC; however, it does have an effect on the brain.
Regardless of the method of consumption (smoking, vaping, eating or drinking cannabis), avoid consuming with nicotine, alcohol, other drugs or health products. This can increase impairment and the risk of other adverse effects.
Store all cannabis (especially edible cannabis, which can be mistaken for normal food or drinks) securely and out of reach of children, youth, and pets.
Don’t drive high.
Consult a healthcare practitioner if you have any questions or concerns regarding cannabis use and your health, have a serious pre-existing medical condition, are taking any other drugs or health products, or are considering using cannabis for medical purposes. To learn more about the risks of cannabis, please consult Canada.ca/Cannabis and Health Canada’s Consumer Information Sheet.
It can take seconds to minutes after consumption to begin to feel the effects, but 10 to 30 minutes to feel the full effects.
Effects can last up to 6 hours, and some residual effects could last up to 24 hours after use.
When cannabis is inhaled into the lungs, it is absorbed directly into the bloodstream and its effects are quickly felt by the brain and body.
To minimize risks or if you are a new consumer, look for a product with less than 100 mg/g (10%) THC, with equal or higher levels of CBD. It can take up to 30 minutes to feel the full effects from one inhalation. Consuming more within this time period can increase the risk of adverse effects.
Exercise caution when consuming products containing between 100 mg/g (10%) and 200 mg/g (20%) of THC. It can take up to 30 minutes to feel the full effects from one inhalation. Consuming more within this time period can increase the risk of adverse effects.
Exercise the most caution with products containing more than 200 mg/g (20%) of THC, such as shatter, wax or distillates. Higher levels of THC can cause greater levels of impairment and increase your risk of experiencing serious adverse effects.
It can take 30 minutes to 2 hours after consumption to begin to feel the effects, but up to 4 hours to feel the full effects.
Effects can last up to 12 hours, and some residual effects could last up to 24 hours after use.
When cannabis is ingested, it takes much longer for it to be absorbed into the bloodstream and for its effects to be felt by the brain and body. When THC is ingested, the body turns it into a stronger form called 11-hydroxy-THC.
To minimize risks, or if you are a new consumer, look for a product containing 2.5 mg of THC or less. It can take up to 4 hours to feel the full effects and consuming more within this time period can increase the risk of adverse effects.
Exercise caution when eating or drinking products containing 2.5 mg to 10 mg of THC. It can take up to 4 hours to feel the full effects and consuming more within this time period can increase the risk of adverse effects.
Exercise the most caution when eating or drinking a product containing 10 mg of THC or more. Higher levels of THC can cause greater levels of impairment and increase your risk of experiencing serious adverse effects.
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