Substances & Substance Use Health

Public Health works at the population level to prevent harms associated with drug and alcohol use. We work to address the social determinants of health, like housing, income, and access to services, that can lead to problems with substance use and poorer health. By doing this, we aim to reduce harms associated with substance use.

What are substances?

Substances are chemical compounds that can alter body and brain function. They can,1

Substances include, but are not limited to,2

To learn more about substances and how they are classified visit The Drugs Wheel.

The substance use spectrum1

People use substances, such as controlled and illegal drugs, cannabis, tobacco/nicotine and alcohol for different reasons, including

Substance use is different for everyone and can be viewed on a spectrum with varying stages of benefits and harms.

Adapted from: Health Canada. (2022, May 10). Substance use spectrum [infographic]. https://www.canada.ca/en/health-canada/services/publications/healthy-living/substance-use-spectrum-infographic.html

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Learn more about substances and how to reduce your risks:

Education and safety

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What is Public Health’s role?

Public Health’s areas of work related to substance use health

Programs, services, and community supports

Have you found discarded needles in the community?

Learn how to safely pick up and dispose of needles.

Helpful links


  1. Health Canada. (2022, June 3). Substance use spectrum. https://www.canada.ca/en/health-canada/services/publications/healthy-living/substance-use-spectrum-infographic.html
  2. Adley, M., Jones, G. & Measham, F. (2023). Jump-starting the conversation about harm reduction: making sense of drug effects. Drugs: Education, Prevention and Policy, 30(4), 347-360. https://doi.org/10.1080/09687637.2021.2013774
  3. Health Canada. (2024, April 3). About substance use. https://www.canada.ca/en/health-canada/services/substance-use/about-substance-use.html
  4. Health Canada. (2014, May 6). Safe disposal of prescription drugs. https://www.canada.ca/en/health-canada/services/safe-disposal-prescription-drugs.html

This item was last modified on July 14, 2025