Babies drink milk old spit up may have to do with drinking milk too fast, pyloric hypertrophic stenosis, increased intracranial pressure and so on. 1. Drinking milk too fast: if the baby is too hungry to eat and drink may eat too fast, the baby’s stomach capacity is relatively small, it may cause the symptoms of spitting up. 2. Pyloric hypertrophic stenosis: infant pyloric hypertrophic stenosis, newborn babies are prone to spit up after eating milk, but appetite is not affected. 3. Increased intracranial pressure: If the baby suffers from brain disease may cause increased intracranial pressure, which will cause spitting up and may appear as jet spitting. The baby drink milk old spit up, there may be other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor’s treatment.