The largest study of its kind has shown cannabis slows lung cancer

http://cannabismd.org/reports/martinez.php-Then I asked him the $64,000 question. I said, "Do you know of any cases of marijuana-only smokers who had lung cancer?" He said "Yes, there is one." Then he smiled, explaining, "He was sixteen years old." We both smiled, knowing a teenager could not possibly have sufficient exposure to marijuana smoke to cause lung cancer--his cancer was clearly due to some other cause.------------google cannabis and lung cancer and see what you get.