The metabolic balances of sulfur in two cases of hepatolenticular degeneration were studied. A positive balance was found in both cases; in one patient submitted to mixed diet, the average was significantly higher than the normal mean. The administration of D-penicillamine promoted a marked increase in the urinary excretion of sulfur, leading to a strongly negative balance. The blood sulfur contents, which were normal in the control periods, showed a progressive increment after D-penicillamine was started.