Marijuana, also called cannabis, has been used for a variety of health conditions for at least 3,000 years. Federal law prohibits the possession of marijuana, and although the U.S. Food and Drug Administration (FDA) hasn't approved marijuana for any health condition, some states and the District of Columbia allow its use for certain health-related purposes. In states that have legalized medical marijuana, its availability is based on decisions made by voters or legislators, rather than on scientific evaluation of its benefits and risks.
For more information on marijuana, visit National Institute on Drug Abuse (NIDA), the lead National Institutes of Health (NIH) agency for research in this field.
Note: This page discusses the use of the cannabis plant, usually by smoking, for health-related purposes. The FDA has approved two synthetic prescription drugs based on a component of cannabis. The use of these drugs is part of conventional medicine; it's not a complementary health approach. For further information about these drugs, see Dronabinol and Nabilone on the MedlinePlus Web site.