Inflammation, necrosis, and sloughing of colonic mucosa; may include component of secretory diarrhea due to prostaglandin release by inflammatory cells; stools usually contain polymorphonuclear leukocytes as well as occult or gross blood. Causes include bacterial infections (e.g., Campylobacter, Salmonella, Shigella, Yersinia, invasive or enterotoxigenic E. coli, Vibrio parahaemolyticus, Clostridium difficile colitis [frequently antibiotic-induced]), colonic parasites (e.g., Entamoeba histolytica), Crohn's disease, ulcerative proctocolitis, idiopathic inflammatory bowel disease, radiation enterocolitis, cancer chemotherapeutic agents, and intestinal ischemia.