Gallstones are hard, pebble-like deposits that form inside the gallbladder. Gallstones may be as small as a grain of sand or as large as a golf ball.
The cause of Gallstones varies. There are two main types of gallstones:
* Stones made out of cholesterol. Gallstones made out of cholesterol are by far the most common type. Cholesterol gallstones have nothing to do with the cholesterol levels in the blood.
* Stones made from too much bilirubin in the bile. Bile is a liquid made in the liver that helps the body digest fats. Bile is made up of water, cholesterol, bile salts, and other chemicals, such as bilirubin. Such stones are called pigment stones.