45-day-old babies spit up a lot of milk may have physiological causes, may also be pathological causes, according to the specific causes of targeted treatment, such as improving the feeding position, the application of drugs, surgical treatment, and so on. 1. Physiological causes: small babies with immature digestive tracts may suffer from gastroesophageal reflux, which can be avoided by elevating the child’s head 15° to 30° after feeding. 2. Pathological causes: If you consider the presence of dyspepsia, pneumonia and other causes, you need to follow the doctor’s instructions for targeted drug treatment. If the child has repeated vomiting, can further improve the abdominal ultrasound, abdominal X-ray and other examinations, if considered the existence of intussusception, pyloric hypertrophic obstruction, etc., then need to further surgical treatment, such as air enema, surgical treatment. If the baby has a large amount of spitting up, it is recommended to consult a doctor in time, after a clear diagnosis for targeted treatment, so as not to delay the condition.