Twenty-day-old babies always spit up may be related to too much milk too quickly, lactose intolerance, gastroesophageal reflux and so on. 1. Eating too much milk too quickly: baby eating too much milk may eat more air, eating too much milk, the baby’s stomach capacity is relatively small, more than the stomach capacity, it is easy to spit up. 2. Lactose intolerance: Breastfed babies may have lactose intolerance, causing spitting up, which may also be accompanied by diarrhea, milk spillage, crying and other symptoms. 3. Gastroesophageal reflux: the baby’s cardia sphincter development is not mature enough, may cause gastroesophageal reflux caused by vomiting, the baby do not put to bed immediately after eating milk, to prevent cause spitting up. Twenty days of the baby always spit up, may also be related to other reasons, it is recommended to go to the hospital in time to identify the cause, under the guidance of the doctor treatment.