Cannabis Facts June 2019: Using cannabis with alcohol and tobacco: A risky combination

Outdoor festival season is upon us, and while there is often an area to consume alcohol and tobacco at outdoor events - this year, a new substance is joining the mix.

Although some people already use cannabis with alcohol and/or tobacco, these cannabis-friendly venues could potentially increase or normalize this mix of substance use. The need to raise awareness of this risky combination is timely and of critical importance.

The risks of using cannabis and alcohol together

Local data from our Wellington-Dufferin-Guelph Public Health (WDGPH) cannabis survey found that over 16 percent of residents who used cannabis in the past 12 months often or always combined cannabis with alcohol, and over 29 percent sometimes did. Almost 1 in 8 (13 percent) of Ontario students in grades 7-12 said they used cannabis and alcohol together at least once in the past year, which rose to 29 percent in grade 12.1  
Using cannabis and alcohol together can lead to more harmful and unpredictable consequences than the use of either substance alone.2,3,4,5 Consuming alcohol before cannabis leads to increased levels of THC in the blood  which can intensify negative effects or cause “greening out”  (feeling nauseous, dizzy and possibly vomiting).2,4,5 Simultaneous use is also associated with consuming increased amounts of alcohol, which can lead to drinking beyond ones usual tolerance and increase the risk for alcohol poisoning.3,4
One of the biggest concerns with simultaneous use of cannabis and alcohol is the increased risk of impaired driving and the risk of collision.2,3,6 Using alcohol and driving or driving after cannabis use is always dangerous. Alarmingly, the number of people in Canada who drive a car after consuming cannabis and alcohol together is on the rise. In 2018, twenty-five percent of people who had consumed cannabis and drove within 2 hours had done so in combination with alcohol, compared to 15 percent in 2017.7 In Washington State, where cannabis was legalized in 2012, polysubstance use (most commonly alcohol and THC) is now the most common type of impairment among drivers of fatal car crashes who tested positive for alcohol or drugs.8

The risks of using cannabis and tobacco together

WDGPH’s cannabis survey found that 21 percent of residents who used cannabis in the past 12 months often or always combined cannabis with tobacco, and 9 percent sometimes did. Canadian data shows that of those who have used cannabis in the past 12 months, 22% have mixed cannabis with tobacco, and 34% have chased cannabis by smoking a tobacco product right after.9 Given the known health risks of smoking tobacco (e.g. nicotine addiction, cancer, cardiovascular diseases and respiratory diseases, etc.), the practice of mixing cannabis with tobacco is concerning.5

A recent study found that people who use cannabis and tobacco/nicotine at the same time report more frequent use of both cannabis and tobacco, and significantly higher rates of cannabis dependence, compared to people who used both drugs on separate occasions or only one drug (cannabis or tobacco/nicotine).10

Actions that WDGPH is taking

WDGPH’s “Talking About Weed” campaign and website includes information about ways to reduce harm from cannabis use, including messaging about not mixing cannabis with alcohol or tobacco. WDGPH shares Canada’s Lower Risk Cannabis Use Guidelines (LRCUG) with community members, community organizations and service providers, which highlights the increased risk of impairment from combining cannabis with alcohol. 
In addition, WDGPH, along with other health units, participated in the Government of Ontario’s consultation on Cannabis Legalization in 2017, where we advocated that cannabis should not be sold alongside other products such as alcohol and tobacco to help mitigate the risks of using these substances together. 


  1. Boak A, Hamilton HA, Adlaf EM, Mann RE. Drug use among Ontario students, 1977-2017: Detailed findings from the Ontario Student Drug Use and Health Survey (OSDUHS). Centre for Addiction and Mental Health [Internet]. 2017 [cited 2019 May 24]. Available from:—osduhs/drug-use-among-ontario-students-1977-2017—detailed-findings-from-the-osduhs.pdf
  2. Public Health Ontario. Evidence Brief: Risk factors for simultaneous use of alcohol and cannabis [Internet]. 2018 August [cited 2019 May 24]. Available from:…
  3. Subbaraman MS, Kerr WC. Simultaneous versus concurrent use of alcohol and cannabis in the National Alcohol Survey. Alcohol Clin Exp Res. [Internet]. 2015 [cited 2019 May 24]. Available from:
  4. Parent Action on Drugs. Stats, facts and talking points about alcohol and other drugs: Parent Action Pack [Internet]. 2018 [cited 2019 May 24]. Available from: FINAL_single_pages.pdf
  5. Canadian Students for Sensible Drug Policy (CSSDP). Sensible Cannabis Education: A toolkit for educating youth [Internet]. 2018 [cited 2019 May 24]. Available from:…
  6. Canadian Centre on Substance Use and Addiction (CCSA). Clearing the smoke on cannabis. Cannabis use and driving: an update [Internet]. 2017 [cited 2019 May 24]. Available from:…
  7. Government of Canada. Canadian Cannabis Survey 2018 Summary [Internet]. 2018 November 19 [cited 2019 May 24]. Available from:…
  8. Washington Traffic Safety Commission. Marijuana use, alcohol use, and driving in Washington State [Internet]. 2018 April [cited 2019 May 24]. Available from:…
  9. Government of Canada. Canadian Tobacco Alcohol and Drugs Survey (CTADS): summary of results for 2017 [Internet]. 2019 Jan 4 [cited 2019 May 24]. Available from:…
  10. Tucker JS, Pedersen ER, Seelam R, Dunbar MS, Shih RA, D’Amico EJ. Types of cannabis and tobacco/nicotine co-use and associated outcomes in young adulthood. Psychol. Addict. Behav [Internet]. 2019 [cited 2019 May 24. Advance online publication (available by request):