The causes of sudden vomiting in children include improper diet, acute gastroenteritis, intussusception and so on, which are analyzed as follows: 1. Improper diet: the child’s gastrointestinal function is weak, if the one-time eating too much or eat greasy, cold food can lead to intestinal dyspepsia, which can be manifested as abdominal distension, vomiting and other phenomena. 2. Acute gastroenteritis: children are susceptible to viral or bacterial infections, resulting in intestinal flora disorders, manifested as abdominal pain, vomiting or diarrhea and other symptoms, which may be accompanied by fever, and in severe cases, dehydration may occur. 3. Intussusception: it can appear suddenly, manifested by severe abdominal pain, crying, accompanied by vomiting, blood in the stool and other symptoms. There may be other reasons for the child’s sudden vomiting, it is recommended to go to the hospital in time for relevant examinations, to clarify the cause of the disease and then actively treat the symptoms.