The founder and director of the Arizona Center for Integrative Medicine, Dr. Andrew Weil, discusses the utility of marijuana. He points out that in recent years, studies have shown potential for treating nausea, vomiting, premenstrual syndrome, insomnia, migraines, multiple sclerosis, spinal cord injuries, alcohol abuse, collagen-induced arthritis, asthma, atherosclerosis, bipolar disorder, depression, Huntington's disease, Parkinson's disease, sickle-cell disease, sleep apnea, Alzheimer's disease and anorexia nervosa. What if cannabis cures cancer?