The results of biochemical, histopathological, oxidative stress and antioxidant defense system markers revealed that acetic acid induced an inflammatory ulcerative colitis indicated by elevated serum TNF-α and IL-1β. The antioxidant defense system parameters in both colon and rectum tissues (GSH, SOD and Px) are decreased as a result of acetic acid administration. On the other hand, the oxidative stress parameter MDA level which is a lipid peroxidation index was markedly increased in acetic acid-administered rats. These results are associated with the histopathological alterations in the colon tissue including inflammatory cells infiltration, hemorrhage, cytomegally, oedema, ulceration and hyperemia. In addition, serum liver function parameters including; AST, ALT and total bilirubin were significantly in both acute and chronic colitis groups. On the other hand, serum albumin concentration was non-significantly affected. Similarly, renal function parameters such as urea and creatinine were also significantly elevated in serum of acetic acid-induced colitis in rats.