Safer Cannabis Use: Marijuana, hash, hash oil

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Author: Canadian Institute for Substance Use Research


Reduce your risk of lung problems, mental health problems and legal issues.

You and safer cannabis use

While using cannabis may be safer than using some other drugs, there are things about using cannabis that can be harmful. Here are some things you can do to reduce your risk of harms and bad experiences.

Before you start...

Be clear about why you want to use
Is it going to help you in some way or make things worse?

Be sure you trust your source
Since cannabis is illegal, it is unregulated. Often products are not tested for quality. Avoid using cannabis if contaminants like mold and mildew are visible.

Try a small amount to test the strength
Some strains of cannabis may have higher THC content and may have a stronger effect than you were expecting. If you know it’s a stronger strain, you can use less and avoid unnecessary smoke and toxins in your lungs.

When using cannabis...

Be discreet
Unless you’re authorized to use cannabis for medical purposes under Canada’s Marihuana for Medical Purposes Regulations, you are breaking the law by possessing and using it. Keep your stash in a safe place and only use it in front of people you know and trust.

Avoid cannabis smoke if possible
Cannabis smoke contains tar and toxins. The safest choice is to use a vaporizer—it delivers the THC in mist form instead of smoke. But they cost a lot of money—$300-800. The second best choice is to smoke it in the form of a joint.

Prevent burns on your lips or fingers
Use a small piece of rolled unbleached cardboard as a filter. Avoid using cigarette filters—they remove 60% of the THC but leave the toxins.

Take shallow puffs, not deep inhalations
About 95% of the THC in the smoke is absorbed in the first few seconds so you don’t need to puff hard or hold your breath.

Leave tobacco out of the mix
Tobacco contains many cancer-causing toxins, so it’s safer to smoke cannabis by itself.

If eating or drinking cannabis...

Take your time
It can be hard to find the right dose when eating cannabis cookies or drinking cannabis tea. You may get much higher for much longer than you wanted to. To prevent this, use a small amount and wait at least one hour to feel the effects before using more.

Cannabis and driving...

Stay away from the steering wheel
Cannabis can impair your motor coordination, judgment and other skills related to safe driving. It’s safest to wait three to four hours after using cannabis before driving or operating machinery.

Things to avoid

Using regularly at an early age
Human brains are not fully developed until early adulthood.

Using cannabis daily or almost daily
Regular habitual use can lead to dependence, meaning you feel you need to use it just to feel normal.

Using cannabis as your main way of having fun or coping with stress
There are healthier ways to enjoy yourself or deal with negative moods.

Using cannabis with alcohol
The effects of cannabis are intensified and may last longer than expected or wanted if you drink alcohol or use other drugs at the same time.

Using cannabis when you are at risk of a mental health problem
Cannabis use may increase the risk of psychotic symptoms for those with a pre-existing vulnerability to psychosis. And, it may worsen the symptoms of psychotic disorders.

Getting help

Self-help tools:


Alcohol and Drug Information and Referral Service:

  • 1-800-663-1441 (BC)
  • 604-660-9382 (Greater Vancouver)


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 Addictions 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