National Center for Complementary and Integrative Health (NCCIH)
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Medical Marijuana

 A hand holding a Marijuana leaf

Courtesy of NIDA

People have used marijuana, also called cannabis, for a variety of health conditions for at least 3,000 years. The U.S. Food and Drug Administration (FDA) hasn’t found that marijuana is safe or effective for treating any health problems. However, some states and the District of Columbia allow its use for certain health purposes. States have legalized medical marijuana because of decisions made by voters or legislators—not because of scientific evidence of its benefits and risks.

It’s challenging to study the health effects of marijuana because of legal restrictions and variability in the concentration of the plant’s psychoactive chemicals. However, recently the Federal Government eased some research restrictions and also began providing researchers with more strains of marijuana. Currently, the quality of health research on marijuana and its components (other than two FDA-approved medications) varies widely by disease.

The National Institute on Drug Abuse (NIDA) has more information on many aspects of marijuana, including how likely people are to abuse it and how chemicals in marijuana affect our brain and body.

Note: This page discusses the use of the marijuana plant, usually by smoking, for health-related purposes. The FDA has approved the prescription drugs dronabinol and nabilone, which are based on a component of marijuana. These medications may be helpful for treating the symptoms associated with cancer or for the side effects of cancer therapies. They are conventional medicines and aren’t a complementary or integrative health approach. For further information about these drugs, see Dronabinol and Nabilone on the MedlinePlus Web site.

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This page last modified June 14, 2016