Three patients with scleroderma were given intravenous infusions of colchicine (2-4 mg/day) for 3 days. Twenty-four-hour urine collections were assayed for total hydroxyproline (HYPRO), an index of collagen resorption, and for nondialyzable polypeptide HYPRO, an index of collagen synthesis. During the colchicine infusions there was a fall in total urinary HYPRO and a slight increase in the per cent nondialyzalbe HYPRO in each patient. The hydroxylysyl-galactosyl-glucose (HGG) to hydroxylysyl-galactose (HG) ratios were not strikingly different in two samples, with the greastest differences in HYPRO excretion. Our results suggested that total body collagen catabolism had diminished without a concomitant decrease in synthesis. In contrast to provocative reports in the literature, these data do not support the hypothesis that administration of colchicine in doses tolerated in man can either inhibit synthesis of new collagen, increase degradation of mature collagen, or be of use in treatment of fibrotic states.