Four-month-old babies who spit up after eating milk may be due to physiological factors such as smaller stomach volume, improper feeding position, or may be due to diseases such as indigestion. 1. physiological factors: due to the small volume of the baby’s stomach content and horizontal position, the milk is prone to reflux. Or may be feeding position is not appropriate, feeding speed is too fast, after feeding position change is big, may baby after eating milk spit up the situation. 2. Indigestion: Indigestion is mainly caused by gastrointestinal dyskinesia, heredity, infection and other factors. The child will appear after meals fullness, some children can appear after eating milk spit up. Four month old babies spit up after eating milk, there may be other reasons, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.