Cannabis Use

If you or someone you know is thinking about using cannabis, here are some things to know to help you make the best decision for your lung health. The best way to avoid any negative health impacts of cannabis is not to use. However if you are going to use we recommend you avoid smoking it. There is still a lot of research needed on non-combustible alternatives for cannabis but from a lung perspective smoking is likely the most harmful. If you do smoke cannabis recreationally don’t expose other people to second hand cannabis smoke, particularly children and other individuals with lung disease.

Smoke is harmful to lung health. Whether it’s from tobacco or cannabis, toxins and carcinogens are released from the burning of those substances. Smoke from cannabis has been shown to contain many of the same toxins, irritants and carcinogens as tobacco smoke.

More research is needed to understand the impacts of smoking cannabis on the lung health of users and those around them. Some studies show that heavy smoking of cannabis may lead to chronic bronchitis and a worsening of chronic lung disease symptoms. It may also lead to symptoms including cough, excessive sputum, wheezing, and a decline in lung function.

The impact of lung health is of particular concern for those who also smoke tobacco. The devastating impacts of tobacco smoke are well known and individuals who co-use may be at an increased risk.

If using cannabis, try to avoid smoking it, if possible.

Second-hand Cannabis Smoke

Second-hand cannabis smoke contains many of the same toxins and carcinogens found in directly inhaled cannabis smoke. While there is no data on the health risks associated with breathing second-hand cannabis smoke, there is concern that it could cause harmful effects, especially among vulnerable populations like children.

More long-term research is needed to fully understand the effects of cannabis smoke, including second-hand cannabis smoke, on lung health.

What are alternatives to smoking?

Alternatives to smoking includes forms of using cannabis that do not require burning or combustion. These may include oils, edibles, drinkables, and vaping.

Cannabis Oils and Edibles

Cannabis edibles are food products that are made with either cannabis or cannabis oils. They are used as an alternative to other ways cannabis is consumed such as smoking or vaping.


Vaping is a means of breathing in cannabis through a vapourizer that heats e-liquid into an aerosol.If you do not smoke cannabis do not start vaping.

Is it safe to consume?

There is a significant chance that non-combustible cannabis (e.g. oils, edibles, drinkables) may be safer for your lungs than smoking it. However, due to the delayed effects, the potential risk for greater impairment is higher. It is important to understand how each non-combustible may affect your body and mind.

Vaping is likely less harmful for your lung health than smoking. While it may be less harmful than smoking, it is likely not harmless. More research is needed to determine whether there are longer term health impacts associated with vaping.

Mixing cannabis and tobacco should be avoided. This increases your risk of harmful respiratory symptoms. Dual use is associated with higher adverse health effects due to higher toxic exposure. Mixing cannabis with tobacco also exposes you to nicotine, making it more addictive.

Cannabis smoke contains more than 450 chemicals and cigarette smoke contains more than 4,000, many cancer-causing. When mixing cannabis with tobacco, you also increase the risks associated with second-hand smoke that contains many poisons including ammonia and cyanide. Third-hand smoke, the leftover residue left on clothes, furniture and carpets can also worsen respiratory symptoms.

Cannabis has properties that may be useful for pain and symptom management for people living with chronic diseases, and it has been legal in Canada since 2001. Learn more.

Harm reduction and prevention

While there is more research needed in this area, smoking of any substance has an impact on the respiratory system and should be avoided. Under no circumstances is smoking harmless to your health.

Canada’s Lower-Risk Cannabis Use Guidelines provide the following recommendations:

  • Most effective way to avoid cannabis risks is to abstain from use
  • Avoid use entirely before age 16 and delay initiation until at least after adolescence
  • Use cannabis products with lower THC or high CBD:THC ratios
  • The use of synthetic products should be avoided
  • Avoid modes of consumption that involve smoking to avoid respiratory effects
  • Avoid deep inhalation which increases intake of toxic materials into pulmonary system
  • Avoid frequent and intense use
  • Refrain from driving for at least 6 hours after cannabis use
  • Populations at higher risk should avoid cannabis use entirely
  • Avoid combining risks which may amplify adverse effects

How to protect your children from cannabis

Children are at a greater health risk for cannabis use. Early and frequent cannabis use is associated with poorer health outcomes. The adolescent brain continues to develop until the mid 20s and cannabis use should be avoided completely before this time. Cannabis smoke may also be an asthma trigger and lead to worsening symptoms, as well as for other lung diseases.

What can second-hand cannabis smoke do?

Second-hand smoke from cannabis has many of the same cancer-causing chemicals as smoke from tobacco. A smoke-free environment is safest and healthiest. Don’t allow smoking in your home or around your child.

What can you do?

What you can do to protect your children from cannabis:

  • Do not smoke around children or pets.
  • Store all cannabis products in a locked area.
  • Make sure children cannot see or reach the locked area.
  • Keep cannabis in child-resistant packaging.
  • Change how you store cannabis as children get older.
  • Make sure your children can’t see or reach the locked cabinet or box.
  • Extra precautions must be taken to make sure any visiting youth under 19 don’t have access to cannabis products.

Cannabis Overview

The term cannabis refers to the many ways in which the Cannabis Sativa plant is prepared for consumption. These include:

  • Marijuana (dried and crushed leaves and flower beds)
  • Hashish (the resin of flower buds)
  • Cannabis extracts (oils and/or waxes)

Cannabis Sativa (hemp plant) has been used for centuries for industrial, medical, and recreational purposes. Cannabis plants produce more than 61 chemicals also known as cannabinoids. The two primary chemicals found in cannabis are Tetrahydrocannabinol (THC) and Cannabidiol (CBD). THC is primarily responsible for the psychoactive effects or ‘high’ associated with cannabis use. Effects from THC vary depending on the dose, means of consumption, strain, whether it has been used with other substances, and the individual (age, pre-existing conditions, etc.,). CBD is the other major compound without the psychoactive effects.

Who’s using cannabis (or marijuana)?

The majority of the general population does not use cannabis. While nearly half (44.5%) of Canadians report ever trying cannabis, only 12.3% had used in the past year.

This rate is higher amongst youth (ages 15-19) and young adults (ages 20-24) with 20% and 30% reporting using in the past year respectively. One in 5 Canadian students (grades 7-12) report having ever tried cannabis. Similar to other substances these percentages increase with grade. In Ontario, 37.2% of grade 12 students report using in the past year.

Individuals that smoke tobacco also have higher rates of cannabis use and/or co-use. Approximately two-thirds of the general population who smoke, report using cannabis in their lifetime. Amongst Ontario students 92% of tobacco users report also using cannabis. Similarly over three-quarters of youth who vape regularly report trying cannabis.

Is cannabis addictive?

While most individuals who occasionally use cannabis do not experience dependence, approximately 5-9% of people that use cannabis will develop dependence. This rate amongst youth it is much higher at 17%. Additionally, about 1 in 5 people seek substance use treatment for cannabis related problems.

Where can I use cannabis?

In Ontario cannabis will be regulated under the Smoke Free Ontario Act (SFOA) and treated like tobacco. That means, individuals are allowed to use cannabis in the same places they are allowed to use tobacco. For a complete list of restrictions under SFOA.

Where can I purchase cannabis?

As of October 17th individuals wanting to purchase cannabis must do so through the Ontario Cannabis Store online. The OCS is the only legal seller of cannabis in Ontario. You must be 19 years of age to access the online store and make a purchase.

Want to learn more?

If you would like to expand your knowledge further, then we encourage you to contact us or read through our sources below.

  1. Canadian Tobacco Alcohol and Drugs Survey (CTADS): 2015 <>
  2. Boak, A., Hamilton, H. A., Adlaf, E. M., & Mann, R. E. (2017). Drug use among Ontarian students, 1977-2017: Detailed findings from the Ontario Student Drug Use and Health Survey (OSDUHS) (CAMH Research Document Series No. 46). Toronto, ON: Centre for Addiction and Mental Health.
  3. Health Canada: About Cannabis
  4. Fischer, B., Russell, C., Sabioni, P., van den Brink, W., Le Foll, B., Hall, W., Rehm, J. & Room, R. (2017). Lower-Risk Cannabis Use Guidelines (LRCUG): An evidence-based update. American Journal of Public Health, 107 (8). DOI: 10.2105/AJPH.2017.303818
  5. McInnis, O., & Plecas, D. (2016). Clearing the smoke on cannabis: respiratory effects of cannabis smoking. Canadian Centre for Substance Abuse.