Chronic relapsing experimental allergic encephalomyelitis (CREAE) is an autoimmune model of multiple sclerosis1 . Although both these diseases are typi®ed by relapsing-remitting paralytic episodes, after CREAE induction by sensitization to myelin antigens1 Biozzi ABH mice also develop spasticity and tremor. These symptoms also occur during multiple sclerosis and are dif®cult to control. This has prompted some patients to ®nd alternative medicines, and to perceive bene®t from cannabis use2 . Although this bene®t has been backed up by small clinical studies, mainly with non-quanti®able outcomes3±7, the value of cannabis use in multiple sclerosis remains anecdotal. Here we show that cannabinoid (CB) receptor agonism using R(+)-WIN...