Gallstones are formed by precipitation of cholesterol or pigment crystals in the gallbladder. Pregnancy, genetic predisposition or rapid weight loss causes alterations of the bile allowing stone formation. Gallstone or crystals (gallstones too small to be detected by x-rays or ultrasound) may block or irritate the tube that drains the gallbladder (the cystic duct), the tube that drains the liver (common bile duct) and the tube draining the pancreas. In turn this can cause cholecystitis (inflammation and infection of the gallbladder), jaundice with infection and pancreatitis. Laparoscopic removal of the gallbladder is curative. Occasionally ERCP is required to look for and treat stones in the common bile duct.