Inflammation response plays an important role in host survival, and it also leads to acute and chronic inflammatory diseases such as rheumatoid arthritis, bowel diseases, allergic rhinitis, asthma, atopic dermatitis and various neurodegenerative diseases. During the course of inflammation, the ROS level increases. In addition to ROS, several inflammatory mediators produced at the site lead to numerous cell-mediated damages. Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is a chronic intestinal disorder resulting from a dysfunctional epithelial, innate and adaptive immune response to intestinal microorganisms. The methods involving indomethacin-induced enterocolitis in rats with macroscopic changes of IBD, myeloperoxidase assay, microscopic (histologic) characters and biochemical parameters are discussed.