January 6, 2020
In follow up to our October 2018 statement on cannabis and health, we want to advise Canadians on ways to reduce the health risks associated with using cannabis, particularly in relation to new cannabis products becoming legally available across the country.
As with other regulated substances, such as alcohol and tobacco, cannabis is not harmless and carries risks. While there is some evidence of potential therapeutic uses for cannabis, evidence continues to emerge on the longer-term health effects of cannabis, highlighting the importance of ongoing research. The only way to completely avoid the risks associated with cannabis use is to not use it.
People who use cannabis should be familiar with the different risks associated with various ways of consuming cannabis extracts, edibles and topical products. How you consume cannabis (e.g. orally vs. by inhalation), how much tetrahydrocannabinol (THC) or cannabidiol (CBD) you consume, and how quickly you consume a product can influence whether or not you experience adverse effects. Start low and go slow. Choose products with a low amount of THC and an equal or higher amount of CBD to minimize health risks and reduce the potential for overconsumption.
Given the recent and ongoing concerns about vaping-associated lung illness—and the limited overall understanding of the short and long-term risks of vaping—the safest approach for people who use cannabis is to avoid smoking or vaping cannabis extracts. Those who choose to vape cannabis extracts should consider the following advice to help reduce risks to their health:
- Use vaping products that have been obtained from legal, regulated sources only. Illegal or unregulated sources are not subject to any control or oversight and may pose additional risks to health and safety.
- Use vaping products for their intended purpose only. Avoid modifying vaping products and do not add substances to products that are not intended by the manufacturer (such as products containing nicotine). If a product is not intended for vaping, do not vape it.
- Limit the amount and frequency of consumption. Initial effects can be felt within seconds to minutes, but full effects can take up to 30 minutes to be felt. Begin with one or two puffs of a vape or joint with 10 percent (100mg/g) or less of THC.
- Always read the label to understand the strength of the product. The concentration of THC (% or mg/g) can be found on the label on products that have been obtained from a legal, regulated source.
- Avoid deep inhalation and breath-holding.
- Avoid consuming other substances, such as alcohol, when using cannabis.
Cannabis products that do not involve inhalation such as orally consumed oils or tinctures, edible cannabis products, topicals or sprays, can be an option to avoid potential impacts on lung health. However, cannabis products that are swallowed or eaten can have psychoactive effects, or effects on mental processes, that can differ from those that are inhaled. Some people may experience stronger and more unpredictable effects from edible cannabis products than from inhaled products. In addition, delays in the onset of psychoactive effects from swallowed or eaten cannabis products can result in overconsumption and increase the risk of poisoning. Edible cannabis products can also carry a higher risk of accidental poisoning, especially in children and pets, because they can be mistaken for regular food and drink.
To minimize the risks associated with using edible or orally consumed cannabis products, consumers should:
- Always read the label to understand the strength of the product. The total amount of THC in a single package of edible cannabis can be up to 10 mg, which would be a large amount for someone consuming cannabis for the first time or infrequently.
- Label and store all cannabis securely. Edible cannabis may look like regular food such as baked goods or candy. Store them securely in clearly labelled containers or in their original, child resistant packaging, away from food products and out of the reach of children and pets.
- Start with small amounts – 2.5 mg of THC or less for products that you eat or drink.
- Wait until you feel the effects before taking more. It may take up to 2 hours to feel the effects of edible cannabis, and up to 4 hours to feel the full effects.
Remember not to drive or operate heavy equipment after using cannabis. Cannabis can impair coordination and concentration, and can impede your ability to make quick decisions. The effects from edible cannabis last 4 to 12 hours, with some effects lasting up to 24 hours.
If you experience any adverse effects from cannabis—including edible cannabis, cannabis extracts or topicals—seek appropriate health care and report side effects from cannabis products to Health Canada.
Finally, when using any type of cannabis product, it is important to remember that like other substances, there is the possibility of developing cannabis dependence or addiction, and that frequent use can cause harm to your physical and mental health. In fact, close to 10% of adults who have ever used cannabis will develop cannabis use disorder. The younger you are when you start using cannabis, and the more often and the longer you use it, the more likely that it will have an adverse impact on your health. People who experience problems related to their use of cannabis can speak to a healthcare provider about evidence-based behavioral treatment and recovery options.
As Canada’s Chief Medical Officers of Health, we encourage all those who use or are considering using cannabis to be aware of the ways they can minimize the potential negative impacts of cannabis use.
Get informed. Protect your health and the health of your family.
Dr. Theresa Tam
Chief Public Health Officer of Canada
Dr. Bonnie Henry
Provincial Health Officer, British Columbia
Chair, Council of Chief Medical Officers of Health
Dr. Brendan E. Hanley
Chief Medical Officer of Health, Yukon
Vice-Chair, Council of Chief Medical Officers of Health
Dr. Janice Fitzgerald
I/Chief Medical Officer of Health, Newfoundland and Labrador
Dr. Heather Morrison
Chief Public Health Officer, Prince Edward Island
Dr. Robert Strang
Chief Medical Officer of Health, Nova Scotia
Dr. Jennifer Russell
Chief Medical Officer of Health, New Brunswick
Dr. Horacio Arruda
Director of Public Health and Assistant Deputy Minister
Ministry of Health and Social Services, Québec
Dr. David Williams
Chief Medical Officer of Health, Ontario
Dr. Brent Roussin
Chief Public Health Officer, Manitoba
Dr. Saqib Shahab
Chief Medical Health Officer, Saskatchewan
Dr. Deena Hinshaw
Chief Medical Officer of Health, Alberta
Dr. Michael Patterson
Chief Medical Officer of Health, Nunavut
Dr. Kami Kandola
Chief Public Health Officer, Northwest Territories
Dr. Evan Adams
Chief Medical Officer, First Nations Health Authority, British Columbia
Dr. Tom Wong
Chief Medical Officer, Public Health, Indigenous Services Canada