The bile secreted by the liver passes through the bile ducts step by step (capillary bile duct – Herring’s duct – interlobular bile duct – hepatic duct – common bile duct), like a river flowing into the sea, and finally enters the duodenum, where it participates in the digestion of fats and fat-soluble vitamins (mainly vitamins A, D, E and K) in food, so that the small intestine can absorb these nutrients. The gallbladder is shaped like a pear and fits immediately underneath the liver. The gallbladder absorbs water from the bile and acts as a “warehouse” to concentrate and store the bile. In addition to being regulated by nerves and hormones, the secretion of liver bile and gallbladder contraction are also regulated by meals. There is an “opening” in the wall of duodenum (duodenal papilla) connected to the common bile duct, and the sphincter of Oddi around the duodenal papilla can relax and contract, just like the “switch” of tap water, to regulate the flow of bile in the common bile duct. When you fast, the flow of bile into the small intestine is reduced by about half, and the other half goes into the gallbladder for storage. When you eat, the “switch” of the duodenal papilla opens and the bile secreted in the liver and the contraction of the gallbladder sends the bile from the “warehouse” to the small intestine through the duodenal papilla. The contraction of the gallbladder and the secretion of bile will be carried out regularly when the three meals a day are regularly scheduled and eaten. If you don’t eat breakfast for a long time or the interval between meals is too long, bile is kept in the gallbladder for a long time and has no “place to use”. The water is absorbed, the bile becomes more and more viscous, and the viscous bile is exactly the “breeding ground” for gallstones.