The gallbladder is a sac located under the liver. It stores and concentrates the bile produced in the liver. Update Date: 03/08/2008Christian Stone, MD, Division of Gastroenterology, Washington University in St. Louis School of Medicine, St. Louis, MO. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.