30 patients with multiple sclerosis smoked 800 mg cannabis cigarettes containing 4% delta-9 tetrahydrocannabinol (delta-9 THC) or placebo in a randomized order for 2 weeks each. The purpose of this study was to determine if cannabis improved pain and spasticity while maintaining similar effects on cognition, deficits, fatigue, mood, movement, and symptoms as placebo. Results indicated that cannabis significantly improved pain and spasticity compared to placebo, but decreased cognitive ability, had an increased rate of adverse events, and increased feelings of highness. All other outcome measures were comparable between treatments.