Glucosamine sulphate, in injectable and oral form, was investigated in a controlled clinical trial in patients with osteoarthrosis. Two groups of 15 in-patients received either 400 mg glucosamine sulphate daily (12 by the I.M. and 3 by the I.A. route) for 7 days, followed by 2 weeks at 1.5 g daily of oral glucosamine sulphate in 3 divided doses, or an I.M. injection daily of a piperazine/chlorbutanol combination for 7 days, followed by oral placebo during the following 2 weeks. Semi-quantitative scoring of pain at rest and during active and passive movements, of restricted function and, where possible, of walking time over 20 meters, were taken as therapeutic activity indices, and tested before and after 1 and 3 weeks of treatment. With both initial parenteral treatments, each symptom significantly improved, with a trend for faster and greater recovery with glucosamine, mainly in restricted function. During the maintenance period, a further significant improvement was recorded in the group receiving glcosamine, whereas with placebo the symptom scores rose to almost the pre-treatment levels. A similar pattern was shown in the measurement of walking speed. It is suggested that injectable and/or oral glucosamine sulphate should be considered for the basic therapy of primary or secondary osteoarthrosis, mainly because it restores articular function to a certain extent.