 Fecal specimens will also be collected just prior to bowel preparation for endoscopycolonoscopy. If the BA patient is already having a Kasai portoenterostomy, done to remove the diseased bile ducts, we would like to take a biopsy of the bile duct. If the patient has a liver biopsy clinically done we would like to keep a 2mm section of it. If the patient has an intraoperative cholangiogram to evaluate the bile ducts we will collect 2.5 cc. of bile fluid. With regards to the controls, who have other intestinal disorders and are also having clinical endoscopies done, we would request a midesophagus biopsy; a biopsy from the antrum and 2 biopsies from the 4th portion of the duodenum. Cell brushings will be taken from the following areas: 2 from mid-esophagus, 2 from lesser curvature of the stomach, 2 from the second portion of the duodenum near the ampulla. 2 from the jejunum 5 cm from the Ligament of Trietz, and 2 from the ileum 10 cm from the ileocecal valve. We will also obtain brushing from the tongue. A sample of saliva will be taken. If the patient is having a colonoscopy done as part of their clinical care we would request a biopsy from the ileum, cecum, and transverse descending rectum. We would also ask for a saliva sample. 