The effect of repeated intravenous infusions of cupric salts was studied in two patients (cousins) with trichopoliodystrophy identified at the ages of 3 days and 2 and-one-half mo, respectively. The intravenous doses of copper were gradually increased and normal or near-normal serum values were achieved after 150 mug/Cu2+/kg were administered daily for 5 days. At that time the hepatic concentration of copper in the two patients increased from 14 to 38 mug/gm of dry weight from 7 to 45 mug/gm of dry weight, respectively, and the muscle homogenate exhibited the capacity to oxidize pyruvate-3-14C. Continued infusions of cupric salts in doses of 190-220 mug/kg/day once or twice weekly were necessary to maintain elevated hepatic and serum concentrations of copper. At 6 mo of age the younger infant had reached a functioning level of 4 mo. The older infant demonstrated progressive loss of neurologic functions and died at 15 mo of age. These observations suggest that the neurologic and biochemical dysfunctions of trichopoliodystrophy may be altered by infusion of cupric salts early in the course of the disease.