The main reasons for spitting up after drinking milk are improper breastfeeding and digestive system diseases. 1. Improper breastfeeding: the baby is still drinking milk swallowing coordination is poor, and the stomach is in a horizontal position, the lower esophageal sphincter is relatively loose, while the pyloric sphincter is relatively developed. If parents do not properly burp when feeding the baby to promote the discharge of gas in the digestive tract or frequent shaking of the baby just after drinking milk, it is easy to lead to spit up after drinking milk. 2. Digestive system diseases: including pyloric hypertrophic stenosis, intestinal obstruction, intestinal infections, including digestive system diseases, can cause the baby to drink the milk can not be in the digestive tract smooth passage, but also because of the baby’s stomach capacity is relatively small, can not accommodate too much milk, so there will be a spit up just after drinking milk. If the situation of spitting up after drinking milk can not be relieved, we should take the baby to the hospital in time to seek medical treatment, by the professional doctor to find out the cause of the disease after targeted treatment.