A small number of infants have milk overflow from the mouth after feeding, the amount is not much, a few infants have milk overflow due to changing diapers and other changes in position a few moments after feeding, such as the general condition of the infant is good, does not affect the growth and development, milk overflow decreases with age and disappears naturally by 6 months after birth, which is a normal phenomenon. Vomiting is different from milk, as milk gushes out of the mouth in a hurry. It is also a common phenomenon in small infants and is related to the anatomical and physiological characteristics of the digestive tract of small infants. Small infants’ stomach volume is small, the position is relatively horizontal, the upper mouth that is the cardia sphincter is poorly developed, the lower mouth that is the pylorus leads to the intestine, its sphincter is better developed. Therefore, the exit of the newborn’s stomach is tight and the entrance is loose, and milk is easily refluxed to cause vomiting. As the baby grows and develops, it gradually disappears after 6 months. Normal infants can vomit if they are not fed or cared for properly. Common causes include too many feedings, too much milk, too large aperture of the nipple, too fast milk delivery, etc.; or milk in the bottle not completely filled with milk, eating air at the same time; or too many changes in position after feeding. Vomiting can be effectively prevented by improving feeding and nursing methods, as well as by picking up the baby after feeding, patting him on the back, letting him burp, and putting him in the right side position. If the vomiting becomes severe, the baby should be examined and treated in a timely manner.