To evaluate the oral glutamine (GLN) on the luminal microbes and bacterial translocation (BT) in short bowel, 45 Wistar rats were utilized in three groups; A (control), and B and C (short bowel, 85% of small bowel resected). The group A was fed with elemental diet (EmD), B with EmD+2% glycine, and C with EmD+2% GLN. The groups B and C were isocaloric and isonitrogenous. Wet weight, DNA, protein, and histomorphometry of the mucosa and parallel microbial culture from cecal contents, caval blood, and tissue blocks of the liver, spleen, and mesenteric lymph nodes were performed on the 5th, 10th, and 15th day. Mucosal growth was higher in group C than B. Colony forming units (CFU) from cecal contents increased more in group B than in C. BTs in A, B, and C were 7/15, 8/15, and 2/15, respectively. Total CFUs in blood and tissues were 5.8X10(4)/g, 5.5X10(6)/g, and 1.8X10(4)/g, respectively. As for BT, the most frequent organism was Klebsiella in A (79.3%), but E. coli in B and C (94.2% and 55.6%). GLN seems to suppress luminal microbes, and reduces BT in short bowel due to enforced barrier function and proliferation of the mucosa.