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 glucosaminene 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). Possible side-reactions were similarly scored upon positive questioning of the patients. Haematology, erythrocyte sedimentation rate, urine analysis and X-rays were recorded before and after treatment. Significant alleviation of symptoms was associated with the use of the active drug at the prescribed dose. Similarly, 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, and no variation in laboratory tests was recorded.