Abstract AIMS To study the effects of glutamine supplemented parenteral nutrition on protein metabolism, small intestinal mucosal morphology, and barrier function in endotoxin ureated rats. METHODS Thirty five male Wistar rats were divided into four groups randomly: group A, normal control, group B, enteral nutrition; group C, non_glutamine TPN; group D, glutamine TPN. Endotoxemia was induced by continuous intravenous infusion of endotoxin at a dose of 2mg/kg per day throught the 5 day study period. The small intestinal bacterial translocation rate, mucosal protein and DNA contents, and the contents of SOD, MDA, ATP and SIgA of mucosal homogenates were determined. Mucosal thickness and villous height were measured with light microscope, and thickness of microvillus were measured with electron microscope.