The entire digestive tract is like a train, of which the esophagus, stomach and duodenum are the three carriages. The esophagus generally has no passengers, are passing through, food after passing through the cardia usually sits in the stomach for half an hour, and then passes through the pylorus into the next carriage, usually the cardia and pylorus these two doors are open in one direction, passengers (food) can not go back, once passed, the door automatically closed. After the food reaches the duodenum through the pylorus, the pylorus closes and a new passenger gets on board in the duodenum, the bile from the liver and waiting in the gallbladder, which will accompany a part of the fatty leader (grease) of the food for the whole journey. The proper operation of the entire digestive train depends not only on the proper functioning of the individual compartments, but also on the opening and closing of the various doors at the right time. If a person’s qi is not in order, if the qi goes up, or if he eats in an unstable state, such as eating while walking, it will affect the function of the digestive tract, causing reflux and leading to disease. The digestive tract is a train that keeps running every day, some people drive fast, some people drive slow, but no matter what, there are times when the train brakes. If the “door” between the carriages cannot close in time because of old age (slack) or rust (infected with H. pylori), the passengers in the carriage behind will be thrown into the carriage before when the brakes are applied in a hurry. If the cardia is not closed tightly, the food in the stomach enters the esophagus, which is gastroesophageal reflux disease (symptoms are mainly acid reflux and heartburn); if the pylorus is not closed tightly, the food in the duodenum returns to the stomach along with bile, which is bile reflux gastritis (symptoms are mainly bitter in the mouth); more serious, if it is a violent emergency braking, there are also cases where the duodenal contents are directly thrown out of the mouth, such as drunken mouth spitting yellow-green bile scenario.