Crohn's disease is an inflammatory disease that can affect any part of the tract from the lips to the rectum (anus). The common part of the tract that is affected is the transition portion between the small intestine and colon. The inflammation may go through the entire intestinal wall from mucosa to the outside of the intestine. The infected area becomes red, swollen, painful and may bleed. Typical of this disease is that it can also be formed inflamed nodules (granuloma) in the intestinal wall. When inflammation will also form scar tissue. The granulomas and scar tissue may cause it to become narrow portions of the intestine. The affected areas can no longer maintain its normal functions, which can cause diarrhea.