The clinical presentation^[6] of ulcerative colitis depends on the extent of the disease process. Patients usually present with diarrhea mixed with blood and mucus, of gradual onset that persists for an extended period (weeks). They may also have weight loss and blood on rectal examination. The inflammation caused by the disease along with chronic loss of blood from the GI tract leads to increased rates of anemia. The disease may be accompanied with different degrees of abdominal pain, from mild discomfort to painful bowel movements or painful abdominal cramping with bowel movements.

Ulcerative colitis is associated with a general inflammatory process that affects many parts of the body. Sometimes these associated extra-intestinal symptoms are the initial signs of the disease, such as painful arthritic knees in a teenager and may be seen in adults also. The presence of the disease may not be confirmed immediately, however, until the onset of intestinal manifestations.