Spitting up after breastfeeding may be a physiological phenomenon, or it may be caused by poor breastfeeding posture, indigestion, congenital diseases and other reasons. 1. Physiological phenomenon: due to the baby’s age, the digestive tract development is immature, the stomach is horizontal and small capacity, the cardia opening is more flaccid, which may cause the baby to spit up after eating breastmilk. In addition, the baby’s vomiting center is not well developed, poor coordination of swallowing muscle groups, may also cause spitting up. 2. Poor breastfeeding posture: If the breastfeeding posture is poor, during the process of breastfeeding, the air may be inhaled into the stomach, the baby a little activity, the phenomenon of spitting up after breastfeeding. 3. Indigestion: When the baby has indigestion, it will easily lead to the accumulation of too much milk in the stomach that can not be emptied in time, and after breastfeeding, there will be spitting up, and accompanied by abdominal distension. 4. congenital diseases: if the baby has congenital developmental abnormalities, such as congenital hypertrophic pyloric stenosis and other diseases, may also lead to the baby after breastfeeding, the situation of spitting up. The baby will spit up after eating breast milk to rule out the physiological phenomenon, parents should take the baby to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor active treatment, so as not to delay the condition.