A hardened deposit of fluid in the gallbladder, a small organ under the liver.
Gallstones are hardened deposits of digestive fluid that can form in the small organ under the liver, called the gallbladder. Gallstones can vary in size and number.
Gallstones may or may not cause symptoms. If they cause a blockage in a duct, you may have sudden, intense pain in your abdomen, right shoulder or back between the shoulder blades. You also may have nausea or vomiting.
People who experience symptoms usually require gallbladder removal surgery. Gallstones that don't cause symptoms usually don't need treatment.