The child always spits up milk may be due to physiological development, acute gastroenteritis, intestinal obstruction and so on. 1. Physiological development: when the child is small in age, the coordination of swallowing muscles is poor, the stomach is in horizontal position, the cardia is loose, the pylorus is spasmodic, the ability to secrete gastric acid and pepsin is poor, which is easy to cause spitting up. 2. Acute gastroenteritis: Acute gastroenteritis can be caused by cold, improper diet, bacterial or viral infection, resulting in nausea, vomiting, indigestion, etc., which can lead to spitting up. 3. Intestinal obstruction: the narrowing or impassability of the intestinal lumen due to various reasons, or intestinal paralysis, etc., can cause intestinal obstruction, resulting in vomiting, abdominal pain and distension, crying and restlessness, and the anus stops defecation. Children always spit up may also have other reasons, such as gastroesophageal reflux, milk protein allergy, lactose intolerance, etc. It is recommended to go to the hospital in time, complete the examination to determine the cause of the disease, and then give targeted treatment or treatment.