There are physiological and pathological milk spillage in babies who fall asleep and spit up milk. As the baby’s digestive system is not yet developed, the stomach is horizontal and the stomach muscles and the lower esophageal sphincter are not yet mature. If you feed your baby too much milk or breathe in a lot of air when feeding, it will easily cause your baby to overflow. If the pacifier opening is too big, your baby eats milk too quickly, turns your baby too much after feeding and adds complementary foods too early, it can also cause your baby to overflow. The overflow caused by the above reasons will not affect your baby’s growth and development and is physiological. You can take measures to improve the symptoms of overflow such as holding your baby upright and patting his back after feeding, giving him a small amount of food, sleeping with a high pillow, putting him in the right side position, and adding complementary foods from 6 months old. If your baby spits up milk frequently, accompanied by poor spirit, poor appetite, fever, cough and other symptoms, and the vomit is green bile or yellow fetal stool-like material, and spits up milk in the form of jets, which affects your baby’s growth and development, you should go to the hospital for examination and consultation in time to avoid delaying your baby’s condition.