Hardened crystal deposits formed from bile pigments, cholesterol, and calcium salts found in the bile duct (choledocholithiasis) or gallbladder (cholecystolithiasis). Commonly called gallstones, they are characterized by severe right upper quadrant abdominal pain or epigastric pain due to transient obstruction of the biliary tract. Other symptoms include nausea, vomiting, hyperbilirubinemia, and elevated alkaline phosphatase and gamma-glutamyl transpeptidase. Gallstones most typically occur in females in the fourth decade of life. They are increased during pregnancy, although they are relatively common and can occur in patients of all ages and across many demographics.

Treatment depends on size, location, and symptoms. Gallstones may end up in the duodenum or pylorus, which may result in gastric outlet obstruction (Bouveret syndrome). Common treatments are stone removal by endoscopic retrograde cholangiopancreatography, sphincterotomy, biliary stenting, and cholecystectomy. Goals of therapy are to prevent recurrent episodes of biliary colic and lower the risk of developing choledocholithiasis, cholangitis, and gallstone pancreatitis.