About Medical Marijuana Marijuana is medicine. It has been used for thousands of years to treat a wide variety of ailments. Marijuana (Cannabis sativa L.) was legal in the United States for all purposes - industrial and recreational, as well as medicinal until 1937. Today, only eight Americans are legally allowed to use marijuana as medicine. NORML is working to restore marijuana's availability as medicine. Medicinal Value Marijuana, in its natural form, is one of the safest therapeutically active substances known. No one has ever died from an overdose. It is also extremely versatile.