A child’s sudden crying may be caused by physical factors such as sudden shock and nervousness, or it may be caused by intestinal spasm or intussusception. 1. Physiological factors: If the child is suddenly frightened by external noise, or if the nerves are overstressed, the child may suddenly cry. If there is no accompanying discomfort, it is generally normal, and parents can calm the child’s mood in time to relieve the crying. 2. Intestinal spasm: the cause of intestinal spasm is not yet clear, may be due to dietary factors, gastrointestinal gas, hunger and other factors. The child may have abdominal pain, abdominal distension and other symptoms, and when abdominal discomfort occurs, there may be a sudden cry. 3. Intussusception: Intussusception is mainly due to abnormal intestinal peristaltic rhythm, pathogen infection, intestinal polyps and other factors. The child may have paroxysmal colic, when the pain is manifested as a sudden cry. There are many reasons why children suddenly cry out, and parents are advised to bring their children to regular hospitals.