Classification Gallstones are concretions formed within the biliary tree (including the gallbladder) and are one of the most common clinical disorders of the digestive system. Clinical manifestations mainly include episodic abdominal pain, acute inflammation, and the following complications if the stone enters the common bile duct: jaundice, cholangitis and pancreatitis; however, most patients can be asymptomatic. Depending on the location of the stones, they are classified as gallbladder stones, intrahepatic bile duct stones and common bile duct stones. From the national survey results in the early 1980s, the incidence of gallbladder stones was about 52.8%, intrahepatic bile duct stones was 36.2%, and common bile duct stones was 11%. Depending on the chemical composition of the stones, they usually include cholesterol stones, bile pigment stones or a mixture of both (mixed stones). The bile duct is a channel for bile production, storage, and delivery to the intestine. The bile duct is one of the most complex areas of human anatomy, with numerous variations not only in the bile duct itself but also in the blood vessels adjacent to it. The gallbladder is a cystic organ containing smooth muscle and elastic fibers, which has the function of storing bile, secreting and absorbing bile components, and driving bile to the intestine through contraction movement. The gallbladder is pear-shaped, about 3-5 cm wide and 7-10 cm long, with a capacity of 30-60 ml and an internal pressure of up to 4 kpa. The contraction of the gallbladder has three forms: rhythmic contraction, which occurs 2-6 times per minute; tonic contraction, which is caused by eating or other biliary stimuli; and peristaltic contraction, which occurs in the neck of the gallbladder and the cystic duct, as if it were a sphincter-like movement. The three forms act alternately to cause the intermittent discharge of bile from the gallbladder. The gallbladder can concentrate hepatic bile 5 to 10 times, and when concentrated, 90% of water and some electrolytes are reabsorbed. Bile is continuously produced by the liver and bile ducts. Bile is an extremely important body fluid, with a daily physiological secretion of about 800 to 1000 ml, or about 30 to 40 ml per hour. Bile is not only involved in the digestion and absorption of lipids and fat-soluble vitamins, but is also the excretion route of many metabolites of harmful substances of endo- and exogenous origin in the body. Usually, liver bile is light-colored, thin and alkaline; gallbladder bile is dark, viscous and relatively acidic. The main component of bile is water, and its main solutes are not only electrolytes and proteins similar to plasma components, but also a large amount of biliary excretion after hepatic biotransformation and other processing, some of which are abandoned metabolic tail products or harmful substances. The composition of bile is very complex, and the solutes that are clinically important include bile acid salts, bile pigments, cholesterol, phospholipids, fatty acids, and various electrolytes and enzymes in bile (such as alkaline phosphatase, leucine aminotransferase, lactate dehydrogenase, and -glutamyl transpeptidase). The flow of bile depends on the rate of bile secretion, the diastolic state of the gallbladder and biliary sphincter and the second segment of the duodenum, and its direction of flow depends on the pressure gradient at each part of the lumen, while its flow rate is proportional to the driving pressure and inversely proportional to resistance. The rate of bile secretion is influenced by habitat and the functional state of the liver and varies according to the species, e.g. herbivores are generally higher than omnivores.