Inflammatory bowel disease (IBD) involves chronic inflammation of all or part of your digestive tract. IBD primarily includes ulcerative colitis and Crohn’s disease. Both usually involve severe diarrhea, pain, fatigue and weight loss. IBD can be debilitating and sometimes leads to life-threatening complications.

Ulcerative colitis is an inflammatory bowel disease that causes long-lasting inflammation and sores (ulcers) in the innermost lining of your large intestine (colon) and rectum.

Crohn’s disease is an IBD that cause inflammation of the lining of your digestive tract. In Crohn’s disease, inflammation often spreads deep into affected tissues. The inflammation can involve different areas of the digestive tract — the large intestine, small intestine or both.

Collagenous colitis and lymphocytic colitis also are considered inflammatory bowel diseases but are usually regarded separately from classic inflammatory bowel disease.

Learn more about IBD at  http://www.mayoclinic.org/diseases-conditions/inflammatory-bowel-disease/basics/definition/con-20034908.