We previously reported that the protective effect of taurine against indomethacin-induced gastric mucosal injury was due to its antioxidant effects which inhibited lipid peroxidation and neutrophil activation. In this study, we examined the effect of taurine on reducing the inflammatory parameters of trinitrobenzene sulfonic acid (TNBS)-induced inflammatory bowel disease (IBD) in rats. To induce IBD, rats were given ethanolic TNBS intracolonically. The rats then received 500 mg/kg/day of taurine per orally. The rats were sacrificed one week after IBD induction. Ulceration and inflammation of the distal colon with formation of granuloma in the vehicle-treated IBD rats after two days of administration of TNBS were observed. Treatment with 0.5 g/kg of taurine by the oral route ameliorated colonic damage and decreased the incidence of diarrhea and adhesions. Colon weight (an index of tissue edema) was markedly increased in the IBD rats after administration of TNBS, but was significantly lower after taurine treatment. Myeloperoxidase (MPO) activity in the vehicle-treated IBD rats was substantially increased compared with that of the control. The taurine-treated animals showed reduced MPO activity (35% lower) when compared with that of the vehicle-treated animals. Taurine treatment decreased basal and formyl-methionyl leucyl phenylalanine (FMLP) stimulated reactive oxygen generation in colonic tissue of the IBD rat compared with vehicle treatment after one week. These results suggest that administration of taurine reduced the inflammatory parameters in this rat model of IBD by increasing the defenses against oxidative insult.