Babies suddenly eat and vomit, the possible causes are: food allergies, acute gastroenteritis, gastrointestinal cold and so on. 1. food allergy: if the baby ate allergenic food, it is easy to cause the body to have an allergic reaction, and then suddenly eat and vomit, in addition, it will also lead to the baby cough, diarrhea and other symptoms. 2. Acute gastroenteritis: usually due to bacterial, viral, parasitic infections, if the baby ate unclean food, cold, spicy and irritating food, it will be easy to trigger an attack of acute gastroenteritis, resulting in inflammation to stimulate the gastrointestinal mucosa to produce a violent gastrointestinal reaction, which leads to a sudden vomiting on eating, and even vomiting and diarrhea. 3. Gastrointestinal colds: usually due to viral infections, resulting in stomach muscle stimulation and contraction, resulting in vomiting symptoms. Therefore, babies may also vomit when they suddenly eat something, and most of them are accompanied by diarrhea symptoms. As you can see, if your baby suddenly vomits after eating, you must pay attention to it, and it is recommended to go to the regular hospital in time.