The most common symptom of Crohn's disease is diarrhea. The intestine may become narrowed and obstructed in Crohn's disease. When Crohn's is located in the colon, the normal function of water re-absorption is impaired, resulting in many liquid stools. Since the lining of the colon also is ulcerated, the diarrhea often contains blood. In the later stages of the disease the colon is often narrowed and shortened, with decreased absorption of water, rectal urgency and poor control of bowel function.
Abdominal pain is another common symptom.
Since the intestine has a muscular coat, it is subject to muscle spasm, just as muscles anywhere in the body. The intestine is also richly supplied with nerve elements. Often, the pain due to intestinal spasm is cramping in nature. Pressure can build up behind the narrowed intestine and produce cramps. Occasionally, the narrowing is so severe that a blockage of the intestine occurs, requiring immediate medical, and less frequently surgical, attention.