The four-year-old baby vomiting in the middle of the night, consider the possibility of pathologic factors, such as indigestion, acute gastroenteritis and so on. 1. indigestion: four-year-old baby digestive function is not fully developed, when the intake of too stimulating, spicy or too cold food, functional indigestion can occur, so the phenomenon of midnight vomiting. 2. Acute gastroenteritis: when the intake of unclean food, can cause the baby gastrointestinal mucosa inflammation, acute gastroenteritis, resulting in baby vomiting. 3. other diseases: some more serious infections such as pneumonia, bacterial meningitis, can cause digestive dysfunction, and even direct invasion of the gastrointestinal tract, secondary to the emergence of acute gastroenteritis, so that the baby vomiting phenomenon. Four-year-old baby vomiting in the middle of the night, there may be other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.