He is a medical marijuana patient and, in fact, the Medical Director of the Oakland Cannabis Buyer's Cooperative in Oakland, California. In this interview he speaks of working with "Waiting to Inhale" a video documentary being produced by PBS. Through this involvement he has been able to interview almost all of the 300 scientist members (from 20 countries) of the International Cannabinoid Research Society. He has learned a lot from them about the science of cannabis-- how it works with the brain, it's lack of side effects, and its safety. It's impossible to overdose as opposed to other substances like heroin, alcohol and penicillin, for example. There are over 80 cannabinoids in the plant, around 8 have different actions that are very helpful with humans and more and more is being understood about the how they work.