The aims of this study were: 1) to obtain an experimental model reproducing the characteristics of chronicity and spontaneous relapses found in inflammatory bowel disease; and 2) to correlate these changes with intestinal motility and bacteria translocation. For this purpose, two groups of Sprague-Dawley rats were used: a treated group, that received two sc injections of indomethacin (7.5 mg/kg) 48 hours apart, and a control group, that received saline. Blood leukocytes, TNF and fecal parameters were monitored for 90 days after treatment. In treated rats a cyclic oscillation of blood leukocytes and TNF concomitant with an inverse correlation of fecal output was observed. Treated rats were then selected either during their highest or lowest blood leukocyte values for motor activity and microbiological evaluation. Controls were obtained in age-matched rats. RESULTS: Rats with high leukocyte levels showed a decrease of motor activity. In contrast, animals with low leukocyte levels presented hypermotility. Bacterial overgrowth accompanied by bacterial translocation was found in the group with high leukocytes, whereas no differences were observed between control and indomethacin group during the lowest leukocyte phase. CONCLUSIONS: We obtained a model of inflammatory bowel disease characterized by a chronic cyclic oscillation of intestinal motility, flora and inflammatory blood parameters. During the high leukocyte stage, motor activity decrease is related to bacterial translocation. This phase is followed by a reactive one characterized by hypermotility associated with a decrease in both bacterial growth and leukocytes. However, as in IBD, this reactions seems unable to prevent a return to relapse.