Crohn's disease causes inflammation of part of the digestive tract. Any area can be affected but most commonly occurs at the end of the small intestine and the right side of the large intestine. Symptoms can include abdominal pain, diarrhea, blood in the stool, fatigue, and weight loss. Crohn's disease can be diagnosed with the aid of a colonoscopy, imaging studies such as a CT scan, blood tests, and stool studies. A variety of medications can be used to treat the underlying inflammation associated with Crohn's disease, although surgery is sometimes required.