In 23 patients who received fat emulsion (Intralipid) intravenously and had subsequent necropsy, the deposition of pigment in the liver was evaluated quantitatively. Pigment was found in hepatic cells (HC) in 14 of 23 patients as well as reticuloendothelial cells (REC) in 22 of 23 patients. There was more pitment deposition in HC in younger children. HC pigment deposition occurred most frequently in patients with acute inflammatory processes within the abdomen. Patients infused with emulsion at rates less than 0.5 g/kg body wt/hr had less pigment deposition than patients infused at faster rates. Neonates infused at rates less than 0.2 g/kg body wt/hr for 24 hr had less HC pigment than neonates infused at higher rates. The quantity of REC pigment bore no apparent relationship to age, clinical diagnosis, rate or total dose of fat emulsion, but was increased in groups infused more than 14 days.