Inclusion criteria for the "disease" arm include a clinical impression of ulcerative colitis that includes assessment of the colon by colonoscopy and biopsy and assessment of the terminal ileum either by ileoscopy or by small bowel radiograph or enteroclysis. Subjects in the "control" arm will only be included if they do not carry the diagnosis of UC or CD, have not had previous gastric or small bowel surgery and are free of gastrointestinal symptoms including unexplained abdominal pain, diarrhea or gastrointestinal bleeding.