The digestive tract refers to the whole process of processing food, which is eaten, polished, transported and transformed into nutrients. The digestive tract is divided into several parts, firstly the oral cavity, where the food is chewed by the teeth and mixed with saliva, and then enters the esophagus, which is the connection between the pharynx and the stomach and is 25 to 30 cm long. The next step is the stomach, which is the main digestive organ of the body. Its scalability can change from 50 milliliters to as much as 2,000 milliliters, so many people eat to too much support for the stomach is also a kind of damage, eat food to seven minutes full, so that the stomach can stretch a degree, not to appear the performance of gastric prolapse. Next is the small intestine, the small intestine mainly plays a role in absorbing nutrients, the food has nutritious substances and then transported to the blood, and then with the blood flow, nutrition of the whole body. Finally, the large intestine plays the role of excreting useless impurities and non-nutritive residues in food. Therefore, the digestive tract is composed of the mouth, esophagus, stomach, small intestine, and large intestine, where the stomach is divided into four parts: cardia, fundus, gastric body, and pylorus.