Should Marijuana be Legalized for Medical Purposes? Marijuana has been used extensively as a medical remedy for more than five thousand years. In the early 1900s, medical usage of marijuana began to decline with the advent of alternative drugs. Injectable opiates and synthetic drugs such as aspirin and barbiturates began to replace marijuana as the physician's drug of choice in the twentieth-century, as their results proved to be more consistent than the sometimes erratic effects of the hard-to-dose potencies of marijuana (Grinspoon). The Marijuana Tax Act of 1937 made cannabis so expensive to obtain that its usage as a medical rem