The book "The Emperor Wears No Clothes" by Jack Herer is where I got much of it. The website www.erowid.org is an excellent online source. not chemically dependant. I'd say that what it amounts to is that 9% of users like it, find it improves their life, and keep using it. It doesn't deposit any if you use a vaporizer, and in any case, most tobbacco in the US is somewhat radioactive and this is theorized as a major contributor to its carcinogenic properties. In addition marijuana has the effect of opening your lungs, whereas tobbaco constricts them. This is why it shows promise in treating asthma and emphysema. I'd like to see that report. It goes against the testimony of a very large number of people who say that other drugs don't help them. For relieving intra-ocular pressure marijuana has been shown to be mroe effective than the current leading drugs. In addition there are more things to consider than just relieving the symptoms. Many drugs have serious side effects. It seems like we'd be hearing a lot more about people unable to have kids given the numbers who smoke pot regularly if this was the case. Where is it well documented?