The gallbladder is an important organ of human body, which has the function of storing and concentrating bile and regulating the pressure of bile duct, and is also an immune organ of human body. The concentration and storage of bile: the mucous membrane of gallbladder has a strong role in absorbing water and electrolytes, so it can concentrate bile. 800ml of bile is secreted by liver daily, and most of it is concentrated and stored in gallbladder. Bile excretion: Bile excretion is regulated by body fluid factors and the nervous system. However, when the gallbladder is inflamed or the sphincter of oddi is dysfunctional, the bile discharge is impaired, the bile is stagnant and the solid component is precipitated, which becomes a cause of polyps or stones. The secretion function of the gallbladder: the gallbladder can secrete mucus substance, about 20ml per day, to protect the mucosa, when the gallbladder duct is blocked, the mucus accumulated in the gallbladder is transparent and colorless, clinically known as “white bile”. Under normal circumstances, the activities of gallbladder and oddi sphincter show a coordinated interrelationship: when oddi sphincter contracts, the gallbladder relaxes and bile is deposited into the gallbladder; when the gallbladder contracts, oddi sphincter relaxes and bile flows into the duodenum. The role of bile: mainly the role of bile salts or bile acids. Bile salts or bile acids can be used as emulsifiers to emulsify fat, reduce the surface tension of fat, so that fat emulsification into micro-droplets, dispersed in aqueous solution so that it increases the area of action of pancreatic lipase; bile acids also class and fatty acids combined to form a water-soluble complex, to promote the absorption of fatty acids, in short, bile is important for the digestion and absorption of fat.