We have this brain-cell killing discussion regularly in this forum. In in-vitro (in glass, like in a petri dish) and in mouse studies, they've discovered that the active compounds in marijuana do kill brain cells, but it appears to be a beneficial killing, a process of helping out with natural cell-pruning process called apoptosis. Here's a link to a thread where we last talked about this subject a week or two ago.

http://boards.cannabis.com/medicinal...ml#post1672767

You might also enjoy reading the sticky at the top of this sub-forum containing health-related abstracts.

As far as marijuana being capable of killing people, the folklore holds that no one has died from it--or that possibly one or two deaths are all that have been officially attributed to it. My personal theory is that, if 14 million people smoke cannabis in the United States, it's entirely likely that someone has probably died from it, but if they had co-morbid conditions like heart or lung disease or other serious medical problems, the cause of death wouldn't necessarily be attributed to cannabis. I doubt we'll ever really have an accurate answer to this question since research isn't allowed on cannabis and since no one's doing large-scale studies or surveys. I personally know two men who were heavy cannabis smokers and who both died of lung cancer within the last six months. Neither of them was ever a cigarette smoker. But they were serious stoners for a period of at least 25 years, smoking it as heavily as plenty of people do cigarettes. We won't know what caused their deaths because it could just as easily have been some environmental sensitivity or genetic predisposition they had.

I think the conclusion everyone needs to draw with cannabis is that it's not without some risks and that it needs to be used with caution just like other medicines and other recreational substances. For people with certain conditions like heart or lung disease and a few others, it does present some risks. But I'm never going to believe that it's as harmful or sinister as alcohol or most other illicit substances. I mostly want people, including the medical community, to see it objectively instead of through the anti-drug propaganda filter and to realize that it's neither all good or all bad.