More states are passing laws that allow people to use medical marijuana. So what does it treat, and who can and should use it? 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, youamp;rsquo;ll get a amp;ldquo;marijuana card.amp;rdquo; 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 and Crohn's disease. - Web MD
