Inflammatory Bowel Disease (IBD) Make an Appointment Find a Doctor Ask a Question Reviewed by Miranda Y. Ku, MD, MPH (May 01, 2013) Inflammatory bowel disease (IBD) is a group of inflammatory disorders that affect the intestinal tract. Inflammatory means to cause irritation, which can be characterized by dilated blood vessels, an increase in white blood cells to the affected area, redness, heat and pain. The two main types of IBD are Crohn’s disease (CD) and ulcerative colitis (UC). There are other conditions that can cause inflammation to the intestinal tract. Crohn’s disease most often affects the end of the small bowel (called the ileum) and the beginning of the colon, although it can also affect any section of the GI tract beginning from the mouth and ending at the anus. Ulcerative colitis is limited to the colon, also called the large intestine. Programs & Services Gastroenterology Program Clinical Trials For more than 100 years, National Jewish Health has been committed to finding new treatments and cures for diseases. Search our clinical trials.