what conditions can medical marijuana treat

Pain is the main reason people ask for a prescription, says Barth Wilsey, MD, a pain medicine specialist at the University of California Davis Medical Center. It could be from headaches, a disease like cancer, or a long-term condition, like glaucoma or nerve pain.

If you live in a state where medical marijuana is legal and your doctor thinks it would help, you’ll get a “marijuana card.” You will be put on a list that allows you to buy marijuana from an authorized seller, called a dispensary.

Doctors also may prescribe medical marijuana to treat:

Muscle spasms caused by multiple sclerosis
Nausea from cancer chemotherapy
Poor appetite and weight loss caused by chronic illness, such as HIV, or nerve pain
Seizure disorders
Crohn’s disease
The FDA has also approved THC, a key ingredient in marijuana, to treat nausea and improve appetite. It’s available by prescription Marinol (dronabinol) and Cesamet (nabilone).

Your body already makes marijuana-like chemicals that affect pain, inflammation, and many other processes. Marijuana can sometimes help those natural chemicals work better, says Laura Borgelt, PharmD, of the University of Colorado.

Medical marijuana may be:

Vaporized (heated until active ingredients are released, but no smoke is formed)
Eaten (usually in the form of cookies or candy)
Taken as a liquid extract