Inflammatory Bowel Disease (IBD) encompasses two different autoimmune diseases: Ulcerative colitis (UC) and Crohn's Disease (CD). Both cause chronic inflammation in the digestive system. Crohn’s disease is most commonly found at the end of the small intestine (ileum) and the beginning of the large intestine (colon), but it can affect any part of the GI tract. Ulcerative colitis occurs in the large intestine where inflammation is usually most severe in the sigmoid and rectum.