Tizanidine was evaluated in a prospective, double-blind, randomized, placebo-controlled trial in 187 patients with MS. Taken orally for 9 weeks and preceded by a titration phase for a period of 3 weeks starting at 2 mg daily, tizanidine produced a significant reduction in spastic muscle tone compared with placebo treatment. Within the effective dose range of 24 to 36 mg given daily in three doses, tizanidine achieved a 20% mean reduction in muscle tone. Approximately 75% of patients, with all degrees of spasticity, reported subjective improvement without an increase in muscle weakness, but there was no improvement in activities of daily living depending on movement. Tizanidine achieved its maximum effect on spasticity within 1 week of the start of treatment; the benefit was maintained for at least 1 week after discontinuation of therapy. A variety of adverse events was recorded by patients taking tizanidine, but these were minor and reversible, and rarely limited treatment. Tizanidine is a well-tolerated and effective drug for symptomatic treatment of spasticity.