Gallstones are deposits like small stones that form in bile, a fluid that helps digestion; bile is stored in the gallbladder, a sac under the liver. Gallstones can develop in the gallbladder or in the bile ducts, which are tubes that carry bile to the small intestine.

Gallstones can be smaller than a grain of sand or as large as a golf ball. They generally do not cause problems unless they block a tube (duct) leading from the gallbladder to other organs. When this happens, abdominal pain and other symptoms develop suddenly.

Gallstones are common. They develop when there is too much cholesterol in the bile for the cholesterol to remain dissolved or when the gallbladder does not empty as quickly as it should. Gallstones are most common in women, people who are obese, older people, people with sickle cell disease, people who have lost weight rapidly, and people who are taking certain medicines.

Most people who have gallstones do not have any symptoms and do not need treatment. If symptoms develop, they usually will include pain in the upper abdomen and are rarely life-threatening. However, pain from gallstones can vary in intensity and may cause vomiting. Gallstones that cause symptoms usually are treated with surgery to remove the gallbladder (cholecystectomy).