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.
In January 2017, the National Academies of Sciences, Engineering, and Medicine published a report(link is external) on the health effects of marijuana and products derived from it. The report summarizes the current evidence on both therapeutic effects and harmful effects, recommends that research be done to develop a comprehensive understanding of the health effects of marijuana, and recommends that steps be taken to overcome regulatory barriers that may make it difficult to do research on marijuana’s health effects.
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.
This page primarily focuses on the use of the marijuana plant, usually by smoking, for health-related purposes. The FDA has approved two prescription drugs, dronabinol and nabilone, 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. In Europe, the United Kingdom, and Canada, a mouth and throat spray called nabiximols, which is derived directly from the marijuana plant and contains two of the plant’s components, has been licensed and approved for the relief of pain and spasticity associated with multiple sclerosis and as an addition to pain treatment for cancer patients. Studies of nabiximols are in progress in the United States.