Not the THC that makes you high, but the other cannabinoids kill cancer cells. You cannot get the effect from smoking, which kills from the heat.
CB2 Receptors act like a target for cannabinoids. Once they bind to the receptor they tell the cancer cell to die, to commit suicide. Cannabis can be used as an anti-cancer medicine.
For additional evidence for the anti-cancer properties of cancer, go to the first-hand abstracts either through our site: http://www.greenmedinfo.com/substance/cannabisor the National Library of Medicine: http://www.ncbi.nlm.nih.gov/pubmed/?term=cannabis+cancer