National Institute of Neurological Disorders and Stroke
Fact Sheet on the Therapeutic Use of  Marijuana for Multiple Sclerosis

There is no evidence that marijuana is effective in modifying the course of MS, but the question has not been studied in an organized way. There have been only anecdotal reports of benefit to some symptoms associated with MS -- spasm and pain -- after use of marijuana. The effect of marijuana on other symptoms of MS such as fatigue or tremor, which cannot be adequately treated with existing medications, is unknown.

Conclusions:

Marijuana is problematic as a therapy for MS. There is no standardized product and method of assuring the bioavailability of its ingredients. The long-term effects of marijuana use by MS patients is unknown.

Other Problems Associated with Inhalation of Marijuana Are:

1. Drug absorption is dependent on deep inhalation of marijuana smoke and may be impractical or, unacceptable for non-smoking patients.

2. Marijuana cigarette smoke contains a complex mixture of over 400 compounds including polyaeromatic hydrocarbons which are carcinogenic. This would be a concern for anyone, but specifically for patients with chronic disorders and/or impaired immune systems.

3. Biologic contamination of marijuana with salmonella and fungal spores has been reported. This again poses a concern for patients with chronic conditions and/or compromised immune systems