One and a half year old baby suddenly vomiting may be physiological reasons, indigestion, acute gastroenteritis and other causes. 1. Physiological reasons: one and a half year old baby’s gastrointestinal tract development is still immature, if not fed at the time, such as eating too much, eating too fast or eating when the baby cries, etc., may lead to one and a half year old baby suddenly vomiting situation occurs. 2. indigestion: if the one and a half year old baby to add complementary foods, parents failed to reasonably control the child’s diet, may lead to the baby indigestion, caused by the phenomenon of sudden vomiting, and also accompanied by abdominal pain, abdominal distension and other symptoms. 3. Acute gastroenteritis: If parents give one and a half year old baby food is too cold or eat spoiled food, it is easy to induce acute gastroenteritis, there may be sudden vomiting symptoms, accompanied by abdominal pain, diarrhea and other symptoms. Sudden vomiting in one and a half year old babies may also have other causes, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.