Medical cannabis (also referred to as medicinal marijuana) is the use of cannabis and its constituent cannabinoids such as THC as a physician-recommended form of medicine or herbal therapy. The Cannabis plant from which the cannabis drug is derived has a long history of medicinal use, with evidence dating back to 2,737 BCE.
Although the extent of the medicinal value of cannabis has been disputed, it does have several well-documented beneficial effects. Among these are: the amelioration of nausea and vomiting, stimulation of hunger in chemotherapy and AIDS patients, lowered intraocular eye pressure (shown to be effective for treating glaucoma), as well as general analgesic effects (pain reliever).
Synthetic cannabinoids are available as prescription drugs in many countries. Examples include Marinol, available in Germany and the United States, and Cesamet, available in Canada, Mexico, the United Kingdom, and also in the United States.