Although infusion of Intralipid has been reported to block reticuloendothelial system (RES) function, it is unclear if this is true at rates used clinically. This study investigates the effect of Intralipid, infused at a rate providing about half of the non-protein caloric needs, on survival and bacterial clearance in septic rats. Continuous infusion of Intralipid (0.9 g/100 g bw/d) or saline (controls) was started immediately after induction of hyperdynamic intra-abdominal sepsis (bacterial agents: E. coli, B. thetaiotamicron). RES function was studied by means of intravenous injection of Selenium-labelled, viable E. coli after 24 or 48 h. Compared to the saline-treated controls, Intralipid did not cause any change in clearance from blood or localisation to liver, spleen or lungs. The 24 and 48 h survival rates were about 80 and 65%, respectively, and similar in the two groups. It is concluded that infusion of Intralipid at a rate close to that used clinically did not impair survival or bacterial clearance in rats with gram-negative sepsis.