Medical marijuana is legal in 20 states, and is used to treat symptoms of multiple sclerosis, AIDS, side effects of chemotherapy, as well as pain, glaucoma, epilepsy, insomnia, and anxiety. Dr. Igor Grant, Distinguished Professor and Executive Vice-Chair of the Department of Psychiatry at UCSD School of Medicine and Director of the UC Center for Medicinal Cannabis Research, tells us about his research into the possible utility of cannabis compounds in the amelioration of certain severe manifestations of disease. And Jim Rendon, author of Supercharged: How Outlaws, Hippies, and Scientists Reinvented Marijuana, talks about the changing attitudes toward marijuana and how the increasing acceptance of medical marijuana is changing the legal and commercial landscape.