Crohn’s (or Crohn) disease is a disease that usually affects the small intestine and less commonly the colon, but it is capable of involving the remainder of the gastrointestinal tract – the mouth, esophagus, and stomach. The chronic inflammation that is the basis of Crohn’s disease causes ulceration, swelling, and scarring of the parts of the intestine that it involves. Other names for Crohn’s disease include granulomatous enteritis, regional enteritis, ileitis, and granulomatous colitis when it involves the colon.