In 1972, the US Congress placed marijuana in Schedule I of the Controlled Substances Act because they considered it to have "no accepted medical use." Since then, 17 of 50 US states and DC have legalized the medical use of marijuana.
Proponents of medical marijuana argue that it can be a safe and effective treatment for the symptoms of cancer, AIDS, multiple sclerosis, pain, glaucoma, epilepsy, and other conditions. They cite dozens of peer-reviewed studies, prominent medical organizations, major government reports, and the use of marijuana as medicine throughout world history.