Baby suddenly spit up serious may be physiological factors, may also be other pathological factors, such as gastrointestinal tract infection, pneumonia and other causes, specific analysis is as follows: 1. Physiological factors: because the baby’s stomach is usually the exit of the tight inlet loose physiological phenomenon, when the baby to eat a large amount of milk, after eating milk and lie down directly, due to the limited capacity of the stomach, can cause physiological gastro-esophageal reflux, can lead to sudden spitting up of the baby serious situation. 2. Pathological factors: if the baby has a digestive tract infection can also lead to frequent spitting up, accompanied by nausea, abdominal distension and other conditions; in addition to pneumonia, there are other brain lesions can also lead to the above situation. When the baby suddenly spit up serious, need to real-time observation of the baby’s situation, if abnormal, to timely medical care, and at the same time to reduce the frequency of breastfeeding, pay attention to scientific feeding.