Medical cannabis (commonly referred to as "medical marijuana") refers to the use of the Cannabis plant as a physician-recommended drug or herbal therapy, as well as synthetic tetrahydrocannabinol (THC) and other cannabinoids. There are many studies regarding the use of cannabis in a medicinal context. Use generally requires a prescription, and distribution is usually done within a framework defined by local laws. There are several methods for administration of dosage, including vaporizing or smoking dried buds, drinking or eating extracts, and taking synthetic THC pills. The comparible efficacy of these methods was the subject of an investigative study by the National Institutes of Health.
Medicinal use of cannabis is legal in a limited number of territories worldwide, including Canada, Austria, the Netherlands, Spain, Israel, Finland, and Portugal. In the United States, 13 states have recognized medical marijuana: Alaska, California, Colorado, Hawaii, Maine, Maryland, Michigan, Montana, Nevada, New Mexico, Oregon, Rhode Island, Vermont and Washington; although California, Colorado, New Mexico and Rhode Island are currently the only states to utilize "dispensaries" to sell medical cannabis.
Seven U.S. states are currently considering medical marijuana bills in their legislatures: Illinois, Pennsylvania, Minnesota, New Hampshire, New Jersey, New York and North Carolina. South Dakota also has several petitions in interest of medical marijuana legalization.
Cannabis has a long history of medicinal use in many cultures. The U.S. federal government, as represented by the Department of Health and Human Services, holds a patent for medical marijuana. Yet, medical cannabis remains a controversial issue worldwide. The Supreme Court ruled in 2005 that the Commerce Clause of the U.S. Constitution allowed the government to ban the use of cannabis, including medical use; the Food and Drug Administration states that "marijuana... has no currently accepted medical use in treatment in the United States".