The authors investigated changes in the serum uric acid (s-UrA) level seen in a Wilson's disease patient who had to undergo oral zinc therapy because of the occurrence of D-penicillamine-induced acute sensitivity reactions, including neutrophilic agranulocytosis, thrombocytopenia, and skin eruptions. Although s-UrA levels were low before oral zinc therapy (mean +/- SD, 1.60 +/- 0.20), they increased (mean +/- SD, 2.63 +/- 0.32) to within normal range (2.8-8.0 mg/dl) after therapy. There were no significant changes in the renal tubular reabsorption of UrA during oral zinc therapy. This therapy also produced an improvement of the decreased cholinesterase (ChE) values usually seen in Wilson's disease. These results suggest that oral zinc therapy can normalize UrA metabolism in Wilson's disease by improving liver dysfunction and increasing UrA synthesis.