A, the physiological structure of the reason 1, the newborn’s stomach is horizontal The newborn’s stomach does not hang down like older children and adults, but is horizontal. This makes the capacity of the stomach smaller and stores less food. 2. The (exit) pyloric sphincter of the stomach is well developed, while the (entrance) cardia sphincter is poorly developed, so it is easy for food to break through the door and cause vomiting. 3, these physiological vomiting, and so on the baby grows up a bit, the stomach pendulous down, intestinal peristalsis of neural regulation and endocrine gastric acid and proteolytic enzyme function gradually enhanced, vomiting symptoms will gradually ease. Second, improper feeding 1, to the newborn baby to eat too much, or improper position resulting in vomiting. 2.Crying, coughing and moving too much after newborns drink milk can also lead to vomiting. 3.During the feeding process of the newborn, the mother’s milk is particularly sufficient and the baby swallows uncoordinatedly resulting in too late to swallow. Generally speaking, babies start to spit up when they are half a month old, and it is usually the most serious when they are two months old, and after three months, the number of spitting up will slowly decrease. 1.Medical diseases: gastrointestinal reaction to drugs, gastroesophageal reflux, cardia flaccidity or spasm, constipation, infection, etc. may cause vomiting. 2, surgical diseases: esophageal atresia, esophageal tracheal fistula, esophageal hiatal hernia, hypertrophic pyloric stenosis, gastric torsion, diaphragmatic hernia, congenital megacolon, anal stenosis or atresia can also cause vomiting in newborns.