Celiac disease is formed by the retention of large amounts of lymphatic fluid in the pleural cavity from the rupture of the thoracic duct fistula or its major branches. The physiological function of the thoracic duct: 1. The main function of the thoracic duct is to infuse fat from the digestive tract into the veins. After the body eats fat, it is broken down into glycerol and fatty acids in the intestine. Among natural fatty acids, short and medium chain fatty acids are hydrolyzed by glycerol tributylase in the stomach, and then completely hydrolyzed into free fatty acids and glycerol after entering the small intestine by the action of pancreatic lipase, intestinal lipase or a small amount of bile salts, due to their small molecular weight and easy diffusion, they can pass through the basal membrane of the small intestinal villi capillaries and be directly absorbed into the portal blood flow without forming celiac particles, while the vast majority of edible fats in general In the small intestine, after complex decomposition, emulsification and recombination, as well as the action of the enzyme system of intestinal mucosa cells and the complex digestive process of re-esterification, outward migration and emulsification, celiac particles are formed and absorbed by the central celiac duct of the small intestinal villi, and then transported to the thoracic duct through the intestinal lymphatic duct and intestinal stem. 60-70% of human fat intake enters the thoracic duct, including neutral fat, free fatty acids, phospholipids, myelin phospholipids, cholesterol esters, etc. 2. The thoracic duct is the main way to return proteins from blood vessels to the blood circulation under normal conditions, and to transport stored proteins from the body into the blood circulation under special conditions. The total protein content of celiac fluid is about half that of plasma protein, including albumin, globulin, fibrinogen, prothrombin, etc. The concentration of electrolytes in celiac fluid is similar to that of plasma, and also contains some sugar and non-protein nitrogen, and contains a variety of fat-soluble vitamins, such as vitamin K, a variety of antibodies and a variety of enzymes. 3. The thoracic duct is the main way for human lymphocytes to recirculate, and the number of lymphocytes returned to the blood through the thoracic duct every day is 10-20 times of the total number of lymphocytes in the blood circulation. The cellular components in celiac fluid are mainly lymphocytes (400-6800/mm3) and a small number of red blood cells (50-600/mm3), and the thoracic duct contains a large number of lymphocytes, 90% of which are stem cells. Therefore, long-term leakage of large amounts of celiac fluid will seriously impair the immune function of the body.