A.D.A.M. Editorial Team: David Zieve, MD, MHA, Greg Juhn, MTPW, David R. Eltz, Kelli A. Stacy, ELS. Previously reviewed by Jenifer K. Lehrer, MD, Department of Gastroenterology, Frankford-TorresdaleHospital, Jefferson Health System, Philadelphia, PA. Review provided by VeriMed Healthcare Network (7/28/2006).