The reason why five-month-old babies spit up a lot may be physiological factors such as eating too much, or pathological factors such as gastrointestinal infections, respiratory infections and so on. 1. physiological factors: five months baby’s digestive system development is not perfect, the lower esophageal sphincter is more relaxed, the pyloric sphincter is more tense, the stomach is horizontal, the capacity is relatively small, coupled with too much to eat, hold the incorrect posture is easy to cause the baby spit up a lot of milk. 2. Pathological factors: patients with gastrointestinal tract infections, respiratory tract infections and other diseases, may cause five-month-old babies spit up a lot. Especially when the baby has fever symptoms, after spitting up milk will appear reluctant to eat milk again, inexplicable crying and so on. If you have a five-month-old baby who spits up a lot of 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.