The colonic pro-oxidant milieu of rats challenged with acetic acid-induced colitis was explored by measuring the pro-oxidant lipid peroxides (measured as thiobarbituric acid reactive substances; TBARS) and the colonic antioxidant defenses including the reduced form of glutathione (GSH) alongside the activities of superoxide dismutase (SOD), glutathione-S-transferase (GST), glutathione peroxidase (GPx), and catalase (CAT). This evidence concerns the gene CAT and colitis.