The etiology of the severe hepatic dysfunction associated with total parenteral nutrition (TPN) remains unknown, but recent studies suggest that taurine deficiency may be associated with the development of cholestasis in experimental animals. That taurine deficiency might also play a role in the development of the severe hepatic dysfunction in human infants receiving TPN as their sole nutritional intake is the subject of the present report. Serial plasma aminograms were obtained from three children with severe hepatic dysfunction associated with TPN, in whom progressive disease led to death after 20, 13, and 14 months. All three children underwent massive intestinal resection for necrotizing enterocolitis, leaving 30, 44, and 17 cm of viable small bowel, respectively. Balanced TPN was given as 20 to 25 g/kg/d dextrose, 1.5 to 2.5 g/kg/d crystalline amino acids, and 2 to 3 g/kg/d fat emulsion; enteral feedings were attempted but were poorly tolerated. Mild cholestasis progressed to severe hepatic dysfunction manifested by hyperbilirubinemia, increased serum transaminases, hypoproteinemia, and abnormal coagulation profiles. Liver histology revealed extensive fibrosis, fatty replacement, and coarse cholestasis, necrosis not being prominent. Serial plasma aminograms revealed markedly elevated plasma levels of methionine (1353, 1168, and 113 nm/mL), low levels of 1/2 cystine (68.4, trace, and 17 nm/dL), and undetectable levels of taurine; plasma levels of branched-chain amino acids were normal.(ABSTRACT TRUNCATED AT 250 WORDS)