What are gallstones? Gallstones usually form in the gallbladder when stored fluid hardens into pieces of stone-like material. Additionally, gallstones can form anywhere in the intrahepatic, hepatic, common bile, or cystic ducts. The liquid, called bile, is used to help the body digest fats. Bile is produced in the liver and then stored in the gallbladder until the body needs to digest fat. At that time, the gallbladder contracts and pushes the bile into a duct that carries it to the small intestine, where it aids in assimilation. Gallstones are a yellow liquid made of fat and cholesterol that convert into stones when collected in the gallbladder. Gallstones are hard, pebble-like deposits that form inside the gallbladder. Gallstones range in size from very small to as large as a golf ball. Additionally, gallstones can move from the gallbladder to the common duct or cystic. However, knowledge about gallstones and their onset, symptoms, diagnosis, treatment and complications is very useful because you will be able to avoid them in the future. Gallstones are more common in women. They are also more common in overweight people and in people with a family history of gallstones. According to (Harvard Women's Health Watch 18.7 (2011): 6-7.) "more than 25 million people in the United States have gallstones, and 65% to 75% of them are women." Gallstones form in the gallbladder when bile is trapped inside it and causes irritation and pressure. In the bile duct, gallstones may be made up of bile pigments and cholesterol salts. Cholesterol is the most common type that is formed when the amount of cholesterol in the bile duct bile. Estrogen increases the concentration of cholesterol in the body more...... and inflammation of the pancreas. Works Cited National Center for Biotechnology Information, August 11, 2011. November 11, 2011 .Marks, Jay W. MedicineNet. June 29, 2011. November 11, 2011 .NDDIC National Digestive Disease Information Center July 11, 2007. November 11, 2011 .—. Robb-Nicholson. Harvard Women's Health Watch. March 11, 2011. November 11 2011 .