Ulcerative colitis (UC) is a multi-factorial inflammatory disease of the colon and rectum. The present study was undertaken to investigate the effect of taurine, an anti-oxidant amino acid, on oxidative stress and the expression of apoptosis-related proteins, pro-apoptotic Bax and anti-apoptotic B cell lymphoma-2 (Bcl-2) in colon tissue in rats with 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis. Rats received taurine (1.5% w/v) in drinking water for 15 days before and 15 days after administration of TNBS solution. Then, colonic myeloperoxidase (MPO) activity, malondialdehyde (MDA) and glutathione (GSH) levels, and Bax and Bcl-2 expression were measured. TNBS-induced colitis caused significantly increased MPO activity and MDA levels and decreased GSH levels in colon tissue compared to controls. Increase in Bax expression and decrease in Bcl-2 expression were detected in colon of rats with TNBS-induced colitis. Taurine treatment was associated with amelioration in macroscopic and microscopic colitis scores, decreased colonic MPO activity and MDA levels and increased GSH levels in TNBS-induced colitis. In addition, taurine reduced the expression of Bax and prevented the loss of Bcl-2 proteins in colon tissue of rats with TNBS-induced colitis. The results of this study show that taurine administration may exert beneficial effects in UC by decreasing inflammatory reactions, oxidative stress and apoptosis.