Patients use marijuana for a variety of painful and debilitating conditions. It has analgesic (pain relieving) effects. It can reduce muscle spasticity; it can also diminish nausea and vomiting and increase appetite. Some of the most common general conditions for which patients use marijuana are as follows: neuropathic pain (pain from a nerve injury), glaucoma, muscle-wasting illnesses, painful muscle spasms, multiple sclerosis, fibromyalgia, and nausea/vomiting caused by illnesses or cancer chemotherapy.