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Questions and Answers

If cannabis is dangerous, why are we legalizing it?

Author: Canadian Institute for Substance Use Research


Yes, cannabis use (like all alcohol or other drug use) carries some risk of harm. The degree of risk and type of harm we might experience depends on certain things including the concentration of THC (short for the chemical compound delta-9-tetrahydrocannabidinol), the amount, frequency of use, and method of consuming.

Cannabis smoke, for example, contains cancer-causing toxins. However, the risk of developing some cancers (e.g., mouth, tongue and lung) is less for cannabis smokers than tobacco smokers, partly because they tend to smoke less than tobacco users. And, while all drugs have an effect on the brain, the particular properties of the drug influence the level of risk of harmful consequences. The negative effects of cannabis on the brain, for example, seem to be less than the effects of some substances such as alcohol.

Legalizing cannabis provides an opportunity to put in place regulations to minimize potential harms. The danger of buying and using any illegal drug is that we can never know for sure what exactly is in it. Cannabis was legal in Canada as of October 17, 2018. Adults (over age 19 in BC) are now permitted to possess up to 30 grams of cannabis in public. Cannabis is regulated by the Province of British Columbia and will be sold through the Liquor Distribution Branch. Cannabis will be tested for quality.

When drugs are produced and obtained inside a regulated system, it is possible for us to know about the contents and dosage of what we are taking. This helps us manage the risks. However, cannabis is still available outside the government system. It is important to know that the quality of cannabis obtained from a dealer or a friend is unknown and may contain contaminants like mold, mildew, or fillers that may be toxic.

The legalization of cannabis also provided us with openings to engage in honest and thoughtful discussions about drug use with our families and communities. When dealing with complex issues, like cannabis policy, no one has all the answers. But as community members, we all have thoughts, feelings and experiences around drugs and drug use to share with each other. Engaging together on an ongoing basis to explore and share ideas will help us discover how to manage use, as individuals and communities, in ways that maximize benefit and minimize harm.

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About the author

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The Canadian Institute for Substance Use Research, formerly CARBC, is a member of the BC Partners for Mental Health and Substance Use Information. The institute is dedicated to the study of substance use in support of community-wide efforts aimed at providing all people with access to healthier lives, whether using substances or not. For more, visit


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