Preliminary studies suggest that the synthetic cannabinoid nabilone might be an effective therapy in patients with fibromyalgia. Skrabek et al. performed a double-blind, randomized, placebo-controlled clinical trial to analyze the effects of nabilone on pain and quality of life in patients with fibromyalgia. After 4 weeks of treatment (0.5 mg once daily in week 1, 0.5 mg twice daily in week 2, 0.5 mg in the morning and 1 mg in the evening in week 3, and 1 mg twice daily in week 4), patients who received nabilone (n = 15) experienced significant improvements in clinical pain, measured on a visual analog scale (P <0.02), Fibromyalgia Impact Questionnaire score (P <0.02) and the 10-point anxiety scale of the Fibromyalgia Impact Questionnaire (P <0.02). After a 4-week wash-out period at the end of the trial, all benefits were lost in the nabilone cohort, which returned to their baseline levels of pain and quality of life. Patients who received placebo (n = 18) experienced no change throughout the study. Although nabilone was not associated with serious adverse effects, some patients did experience drowsiness, dry mouth, vertigo and ataxia as a result of treatment.