I have been a heavy cannabis smoker for about 6 years and after the first 4 years I started to worry about lung cancer... then I came across that widely publicized study by dr. Tashkin and I convinced myself that it was pretty harmless. Now, a few years later I'm starting to reconsider. I am in no way real knowledgeable in science but let me give my take on this issue. When you constantly expose your lung tissue to smoke, over the years that lung tissue will mutate into new tissue, a different kind of tissue, the kind of tissue where tumors are more likely to develop later in life. People with stomach acid reflux, who are at risk for espohagal (spelling?) cancer, have similarly developed a new type of tissue lining their esophagas, as a result of years of burping up too much stomach acid. It is this sort of tissue that the body creates in response to environmental factors that leads to pre cancerous mutations. Again, I am not a doctor and I haven't researched this thoroughly, but this is the opinion I have formed from what I do know. Tell me, why are cigerettes so much worse for you? Is it the nicotine? When you burn plant matter and inhale the smoke you are putting hundreds of different chemicals in your blood stream, and you are irritating your throat and lungs, regardless of whether the plant matter is tobacco or cannabis. In my 6 years of heavy weed smoking the two most harmful things I have done I would say were gravity bong hits and smoking resin out of my bowl. I feel like those two activities have really stressed out my lungs. I'm 24, still young I guess, but I really think I'm done with smoking. I will cook weed into oil and vaporize and get high that way but I just don't think I can continue the smoking under the pretense that "it doesn't cause cancer because there is no documented case of it." I don't want to be the first one! Since this actually IS a matter of life and death I think I'm gonna need a lot more scientific proof than one study a few years ago. How did Tashkin conclude that his subjects weren't at increased risk? Doesn't it cost thousands of dollars to scan somebody for tumors? Maybe I missed it but I have no idea how exactly Tashkin determined that these heavy smokers weren't at risk.

I'm not trying to argue with anyone.. I will advocate cannabis to the death.. but as magical and wonderful as the plant is, it's still smoke in your lungs.