Intrahepatic cholestasis is a condition often observed in patients receiving parenteral nutrition, especially in new born babies who are underweight (< 1,000 g.) Some authors find an alteration in the amino acids transulphuration passage, which gives rise to a deficit of taurina. This makes it impossible to achieve a correct conjugation of toxic biliary acids. The access of nutrients to the liver may have an effect on this. An experimental study on rats was performed, administering an oral diet at the expense of lipids (20% Intralipid, 60% of caloric needs) and glucose (40% of caloric needs) in one group, another group received amino acid supplements to this diet (16N) at a proteic rate of 2 gr/kg of weight and day orally, with an identical diet to the above, except that the proteic intake was intraperitoneal. Two control groups were established. We found a microvacuolization in hepatic fat with the help of an electronic microscope in the groups lacking proteins and those with oral or intraperitoneal supplements of amino acids, as well as an increase in plasmatic AST.