The active ingredient in cannabis is THC (delta-9-tetrahydrocannabinol) which can alter the way you feel, think, and behave. Typically, the dried leaf mixture is smoked in hand-roll joints, pipes, or bongs. Smoking is the preferred method because THC can quickly enter the bloodstream and travel to the brain than when cannabis is ingested with food or drink.2,3

Cannabis can also be mixed with tobacco and smoked together. When used together, there is a risk of developing nicotine dependence. The increased exposure to tar and carcinogens can cause even more damage to respiratory and cardiovascular systems.4

Even if they are not used together, smoking cannabis alone can lead to cigarette smoking and the smoking cigarettes first can also lead to cannabis smoking.4,5

Cannabis is harmful, but the evidence seems to suggest that it is far less harmful than cigarettes. Consider the pros and cons below and YOU be the judge.


  • Cannabis has been shown to be effective for medicinal purposes. It is used for relieving pain and nausea associated with HIV/AIDS and cancer treatments.2


  • Contrary to popular belief, cannabis can be addictive. It can also be hard to quit with withdrawal symptoms such as cravings, irritability, and anxiousness.2,3 Sounds familiar? These are similar withdrawal symptoms that cigarette smokers experience when quitting smoking.
  • A cannabis smoker tends to inhale more smoke and holds the smoke in longer than a cigarette smoker. So, the smoke goes deeper in the lungs and there are greater amounts of carbon monoxide and tar damaging the respiratory system. Cannabis smokers can suffer from daily cough and phlegm production, chest illness, and lung infections.2,4
  • Cannabis smoke tends to be unfiltered, which can be even more toxic and carcinogenic than cigarette smoke.2,3 There are 33 known carcinogens in cannabis smoke!6
  • Cannabis use can cause impairments in attention, thinking, learning, and memory. In young people, long-term use may even cause permanent brain damage!2,3 It’s no surprise that cannabis use is linked with an increased chance of dropping-out of school and more missed days from work.3
  • Heavy cannabis use can cause hallucinations and paranoia. For people who are at a higher risk of developing schizophrenia, cannabis use can bring on the symptoms and worsen the condition.3



  1. Ialomiteanu, A.R., Adlaf, E.M., Hamilton, H. & Mann, R.E. (2012). CAMH Monitor eReport: Addiction and Mental Health Indicators Among Ontario Adults, 1977-2011. Retrieved June 13, 2014 from
  2. Centre for Addiction and Mental Health. (2012). About Marijuana. Retrieved June 13, 2014 from
  3. National Institute on Drug Abuse. (2014). DrugFacts: Marijuana. Retrieved June 13, 2014 from
  4. University of Washington Alcohol & Drug Abuse Institute. (2013). Tobacco and Marijuana. Retrieved June 13, 2014 from
  5. Leatherdale, S., Hammond, D.G., Kaiserman, M., & Ahmed, R. (2007). Marijuana and tobacco use among young adults in Canada: are they smoking what we think they are smoking? Cancer Causes & Control, 18, 391-397.
  6. Tomar, R.S., Beaumont, J., Hsieh, J.C.Y. (2009). Evidence on the carcinogenicity of marijuana smoke. Sacramento, CA: California Environmental Protection Agency. Available: