Ulcerative Colitis is an inflammatory disease that affects the colon and the large bowel and is characterized by inflammation and ulceration of the most superficial layer of the colon. Symptoms include diarrhea with or without rectal bleeding and, frequently, abdominal pain. Ulcerative colitis can affect only the lower part of the colon and rectum – in that case, it is called ulcerative proctitis. When the disease affects only the left side of the colon, it is called distal or limited colitis. If it involves the whole colon, then it is called pancolitis.

Ulcerative colitis differs from another bowel inflammatory disease: Crohn’s disease.

In ulcerative colitis, only the colon is affected. The inflammation occurs at its worse in the rectum and extends all throughout to the colon.

Crohn’s disease can affect any portion of the gastrointestinal tract, including the small intestine, and there may be some areas in the intestine that are not sick, the so- called “saved” areas.
Ulcerative colitis affects only the most superficial layer of the colon while Crohn’s disease may affect full thickness of intestine wall. Ulcerative colitis and Crohn’s disease differ from spastic colon or irritable colon syndrome, which is a disturbance of motility of the intestinal tract. Irritable colon syndrome has no relation with ulcerative colitis or Crohn’s disease.