Amitriptyline and cyclobenzaprine have shown some efficacy in treatment of the generalised pain syndrome, fibromyalgia. The aim of this study was to examine the efficacy of antidepressant dosages of the serotonin re-uptake inhibitor citalopram in fibromyalgia. In a double-blind, placebo-controlled study 22 patients with fibromyalgia were randomized to treatment with citalopram for 4 weeks at a dosage of 20 mg a day while 21 received placebo. After 4 weeks the dosage was increased to 40 mg for a further 4 weeks if the subjects did not report a marked improvement. After the end of treatment (8 weeks) no changes were observed in self-assessment of symptoms, physician's global assessment, tender points, Beck depression score or voluntary muscle strength and no differences were observed between the groups. Citalopram showed no demonstrable effect on this group of pain patients. The strength of the study was sufficient to exclude an effect of citalopram of more than 1 steps of 10 on the categoric scales for pain, fatigue and general condition (95% confidence limit), which indicates that the sample size was sufficiently large.