Yeah...I found this on "google"
Medical benefits of marijuana
Anecdotal evidence for the beneficial effects of marijuana eventually led to the design of controlled scientific studies to examine the benefits of marijuana compared to other treatments. A 1997 review of 6059 marijuana-related articles in the medical literature revealed 194 titles on antiemetic properties, 56 on glaucoma, 10 on multiple sclerosis, 23 on appetite, and 11 on palliative or terminal care.2 Numerous studies have been performed since that time, with most concentrating on the analgesic properties of cannabis and its derivatives.
Antiemetic (anti-nausea) use
Early on, THC had been shown to be effective for some patients who suffered nausea from cancer chemotherapy treatments. However, the narrow window between the anti-emetic dose and that which caused unwanted psychic effects made THC difficult to use.3 In some studies, negative side effects occurred in up to 81% of patients.4 In one of the few studies using smoked marijuana, 20% of patients dropped out of the study, while another 22% reported no relief of nausea symptoms.5 The advent of serotonin 5-HT3 receptor antagonists as new and more powerful anti-emetic drugs that were free of unwanted psychic effects has made cannabinoid use less attractive. For this reason, physicians virtually never prescribe marijuana or THC as an antiemetic for use by chemotherapy patients.6
Multiple sclerosis
Studies have shown that cannabis can relieve muscle pain and spasticity in patients suffering from multiple sclerosis7 and can control tremors in multiple sclerosis animal models.8 However, a study in ten patients with spastic multiple sclerosis showed that smoking marijuana further impaired posture and balance in those patients.9 In addition, MS patients who used marijuana had a greater number of psychiatric diagnoses and a slower mean performance time on standard neurological tests.10 Some randomized, double-blind, placebo-controlled, parallel group crossover trials have found no significant improvement of MS symptoms during cannabis plant extract use. However, in some trials patients did show an increase in aggressive behavior and paranoiac tendencies in a standard psychological test.11 Another placebo-controlled study, examining the effect of a cannabis extract on spasticity in MS, found a positive partial relief of symptoms in 40% of patients.12 A 10-week, placebo-controlled study of MS patients found that 42% withdrew due to lack of efficacy, adverse events and other reasons. Patients reported 292 unwanted effects, of which 251 were mild to moderate, including oral pain, dizziness, diarrhea, nausea. Three patients suffered five serious adverse events, including two seizures, one fall, one aspiration pneumonia, one gastroenteritis. Four patients had first-ever seizures. A minority of patients received some relief of symptoms.13 So, overall, studies show that a minority of multiple sclerosis patients can receive some symptom relief through the use of marijuana extracts or THC, although a significant percentage of patients suffer unwanted adverse effects.
Glaucoma
THC has been shown to reduce intraocular pressure in laboratory animals and humans who have glaucoma.14 However, it was found that intraocular pressure was reduced only when patients stayed under the effects of THC almost continuously.15 Since the early studies, more effective medications, such as 13-blockers and prostaglandins, have been developed to control intraocular pressure. Obviously, glaucoma medications that don't require one to be continuously high are preferable to those that have unwanted side effects.
Appetite
Regular marijuana users are aware of the phenomenon known as the "munchies." Laboratory studies have shown that THC does increase the appetite (not a good thing for most of us).16 However, for those suffering from debilitating diseases, such as AIDS-related wasting syndrome, THC has been shown to be effective in maintaining body weight.17
Analgesia (pain relief)
Some clinical studies have indicated that THC has some analgesic activity in patients with cancer.18 However, there is a narrow therapeutic window between doses that produce useful analgesia and those that produce unacceptable central nervous system effects. Several studies have shown improvement of pain at higher doses,19 while others have shown no effect or a negative effect at higher doses compared with placebo.20