What is colitis disease?
The immune system mistakes food and bacteria in the intestine for harmful substances and subsequently attacks it, causing inflammation and ulcers, states the Crohn’s and Colitis Foundation of America. This is why it is considered a type of irritable bowel disease. Colitis disease only affects the lining of the large intestine, or colon. Other parts of the intestine are not affected.
Sources: ccfa.org, webmd.com