Ulcerative colitis differs from Crohn's colitis in several ways. In ulcerative colitis the disease is limited to the mucosa and, occasionally, the submucosa; Crohn's colitis may involve all layers of the large intestine. Ulcerative colitis almost always begins in the rectum, is diffuse, and spreads proximally. Crohn's colitis may spare the rectum and has a patchy distribution. Perianal fistulas and ulcers are rare in ulcerative colitis but are common in Crohn's colitis. Granulomas and giant cells are not found in ulcerative colitis but are seen in the majority of patients with Crohn's colitis. Colonic and extraintestinal symptoms in the two illnesses may be indistinguishable but growth failure is far more severe in Crohn's colitis and may precede intestinal symptoms by months to years. Cancer of the colon is a risk in patients with either ulcerative or Crohn's colitis but is far more common in the former. It is important to distinguish between ulcerative colitis and Crohn's colitis because response to treatment and prognosis are different. Although neither condition can be cured by medical management, patients with ulcerative colitis may respond more frequently. Unfortunately, in the pediatric age range most cases of ulcerative and Crohn's colitis may be classified as moderate to severe. Fortunately for patients with ulcerative colitis, total colectomy with ileostomy will result in cure of illness. Patients with Crohn's colitis who require surgery may obtain remission of symptoms, but the disease is likely to recur in the small intestine.