Inflammatory bowel diseases

The most common types of IBD are ulcerative colitis and Crohn's disease. The diseases are similar but affect different parts of the digestive system. Ulcerative colitis affects the large intestine and rectum. Both ulcerative colitis and Crohn's disease usually are characterized by diarrhea, rectal bleeding, abdominal pain, fatigue and weight loss. For some people, IBD is only a mild illness. For others, it's a debilitating condition that can lead to life-threatening complications.