A preliminary trial of oral zinc supplementation was conducted in twenty-four patients with chronic, refractory rheumatoid arthritis. Zinc sulphate (220 mg three times daily) or placebo capsules of identical appearance were added to pre-existing therapy for 12 wk. This double-blind trial was followed by an open 12-wk period when all subjects took zinc. During the double-blind phase, zinc-treated patients fared better than controls with regard to joint swelling, morning stiffness, walking time, and the patient's own impression of overall disease activity. The indices and joint tenderness also improved with zinc treatment in both groups of subjects during the second 12-wk period. These encouraging results indicate that oral zinc sulphate deserves futher study in patients with active rheumatoid arthritis.