Four-year-old babies vomit as soon as they eat, most likely caused by gastroesophageal reflux, acute gastroenteritis, intestinal obstruction and other diseases. 1. Gastroesophageal reflux: it is a common cause of four-year-old babies vomiting when they eat, mostly due to colds and other causes. You can take fewer meals, semi-fluidized diet, with easy-to-digest food as the main focus. 2. Acute gastroenteritis: many babies with acute gastroenteritis start with vomiting, followed by fever, diarrhea, abdominal pain and other symptoms. 3. intestinal obstruction: it is a common surgical acute abdominal disease that causes babies to vomit when they eat, manifesting itself in violent vomiting, which can be projectile, and at the same time, abdominal pain is obvious, stopping gas defecation. The four-year-old baby vomits when he eats, there may be other reasons, it is recommended to consult a doctor in a timely manner, improve the examination, clarify the cause of the disease, and if necessary, active treatment.