The efficacy and tolerance of oral glucosamine sulphate were tested against placebo in a prospective double-blind trial in 20 out-patients with established osteoarthrosis. Two capsules of either glucosamine sulphate (250 mg) or placebo were administered 3-times daily over a period of 6 to 8 weeks. Articular pain, joint tenderness and restricted movement were semi-quantitatively scored 1 to 4 every 3 days, and individually averaged over the treatment period (overall composite score). Hematology, erythrocyte sedimentation rate, urine analysis and X-rays were recorded before and after treatment. Patients given glucosamine sulphate experienced earlier alleviation of symptoms compared with those who had placebo. The use of glucosamine sulphate also resulted in a significantly larger proportion of patients who experienced lessening or disappearance of symptoms within the trial period. No adverse reactions were reported by the patients treated with glucosamine.