Cannabis and cancer risk

  • Further research is needed to help us understand the link between cannabis and cancer as currently there are a lot of unknowns.
  • Long-term, heavy cannabis use may raise the risk of testicular cancer.
  • It's unclear if smoking cannabis can cause lung cancer.
  • Potential cancer risks are summarised in our technical report here


Lower risk use

Every form of cannabis use poses risks to people’s health. The only way to completely avoid these risks is by choosing not to use cannabis. 

If you choose to use recreational cannabis, you can lower your risk by following these points:

  • You’ll lower your risk of cannabis-related health problems by not starting to use cannabis until after 25 years. The earlier in life people begin using cannabis, the higher their risk of serious health problems. The more frequently you use cannabis, the more likely you are to develop health problems, especially if you use it on a daily or near-daily basis. Minimise use as much as possible.
  • Smoking cannabis is the most harmful way of using cannabis because it directly affects the lungs. If smoking avoid deep inhalation and long holding of the breath.
  • Don’t mix cannabis, tobacco and alcohol. This can increase the risk of long-term health issues, and drinking and smoking tobacco together raises the risk of cancer many times more than drinking or smoking alone.
  • Completely avoid cannabis use if you have a personal or family history of cannabis use, or are pregnant.
  • Don’t use synthetic cannabis.
  • For more ways to lower your risk see here.

These lower risk guidelines have been adapted from Fischer, B. et al. (2017). Lower-Risk Cannabis Use Guidelines (LRCUG): An evidence-based update. American Journal of Public Health, 107 (8). 

For more information on legalising cannabis and how it affects our health, visit the website of Royal Society Te Apārangi and the Chief Science Advisor.