Crohn's disease can develop anywhere in the digestive tract, including the esophagus, stomach, and even the mouth. But it usually affects the lower end of the small intestine and the beginning of the large intestine, or colon. This makes it different from ulcerative colitis, which only affects the colon.
Your symptoms depend on which part of your digestive tract is affected. Crohn's can also affect other parts of your body, such as skin, eyes, joints, and liver.