Sudden vomiting in babies may be related to physiologic vomiting, or it may be due to indigestion, acute gastroenteritis and other causes. 1. Physiological vomiting: the gastrointestinal tract of younger babies is still immature, if there is improper feeding, such as eating too much at once, eating too fast, or eating when the baby is crying, it may cause physiological vomiting. 2. Indigestion: commonly found in babies who have added complementary foods, if parents fail to reasonably control the child’s diet, resulting in indigestion, the baby will cause sudden vomiting, which can also be accompanied by abdominal distension, abdominal pain and other symptoms. 3. Acute gastroenteritis: If the food given to the baby is too cold, or eat spoiled food, it is easy to induce acute gastroenteritis, which may show the symptoms of sudden vomiting, and can be accompanied by abdominal pain, diarrhea and other symptoms. Sudden vomiting of the baby may also have other causes, if frequent vomiting symptoms, or accompanied by other obvious discomfort, should go to the regular hospital as soon as possible, after diagnosis of the cause, under the guidance of the doctor for targeted treatment.