Canadian authors estimated the patterns and prevalence of Cannabis sativa (cannabis) use among patients with multiple sclerosis. Two hundred and twenty patients were surveyed. Seventy-two subjects (36%) reported having used C. sativa for any purpose; 29 respondents (14%) reported continuing use of C. sativa for symptom treatment. Medical C. sativa use was associated with male gender, tobacco use and recreational cannabis use. The symptoms reported by medical C. sativa users to be most effectively relieved were stress, sleep, mood, stiffness/spasm and pain.