During colitis, epithelial function is impaired, leading to increased bacterial translocation. Recent studies have shown the important role of proinflammatory cytokines and chemokines, including RANTES (regulated on activation, normal T-cell expressed and secreted), in inflammatory bowel diseases (IBDs). In this study, we evaluated the role of Met-RANTES, an antagonist of the RANTES receptor, on the impairment of bacterial translocation in a rat model of colitis. Rats were randomly assigned to 3 groups. group 1 = control, group 2 = experimental colitis, and group 3 = colitis plus Met-RANTES treatment. On day 7 after colitis was induced, plasma tumor necrosis factor-α colon tissue myeloperoxidase and portal blood endotoxin levels were measured. Lymph node, liver, and spleen culture quantified bacterial translocation. Met-RANTES treatment resulted in significant decreases in colonic damage as well as bacterial translocation in experimental colitis. These results suggest that chemokine receptor antagonists may potentially be useful in the treatment of IBDs.