Crohn’s disease is a chronic inflammatory bowel disease (IBD) characterized by inflammation of the digestive, or gastrointestinal (GI) tractCollectively referring to the mouth, esophagus, stomach, small and large intestines, and anus.. In fact, Crohn’s can affect any part of the GI tract, from the mouth to the anus, but it is more commonly found at the end of the small intestine (the ileum) where it joins the beginning of the large intestine (or colon).