［ABSTRACT］ Objective To examine The impact of alanyl-glutamine-enriched enteral nutrition on intestinal permeability in patients after abdominal operation . Methods Two hundrus and sixteen patients undergone abdominal surgery were randomly divided into three groups and received conventional alanyl-glutamine-enriched enteral nutrition (GLN group), enteral nutrition (EN group) and parenteral nutrition(PN group) with isonitrogenic(0.2gN•kg-1•d-1) and isocarloric(125.4kJ•kg-1.d-1) support from postoperative day (POD) 3 to POD 11.On the day before operation POD 7and POD 12, 10g of lactulose and 5g of mannitol were given ,and 6-hour urine after administration was collected for detecting lactulose / mannitol (L/M)ratio. Results Elevated lactulose/ Mannitol (L/M) ratios were found in all the patients at POD7 as compared to POD l. The elevated ratio returned to control level in EN group and GLN group by day 12, but still remained high in PN group patients at POD12. Conclusions L/M ratio increases in the early period after surgical trauma. Enteral nutrition can provide a better protection against intestinal permeability. And alanyl-glutamine-enriched can improve such protection against intestinal permeability.