The baby spit up with sour taste, consider is physiological or pathological factors, physiological factors such as excessive intake; pathological factors such as indigestion, etc., can lead to the baby spit up with sour taste. 1. physiological factors: when the baby intake, coupled with the special physiological structure of the baby’s stomach, resulting in the baby is prone to spit up, and at this time the milk in the stomach is not fully digested, it will send out a sour taste. 2. Pathological factors: the existence of the baby indigestion, will make the stomach of the milk digestion slow, once the occurrence of vomiting in the stomach undigested milk, can be manifested in the vomiting of the milk has a sour taste of the situation. The baby spit up milk with sour taste, there may also 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 to give targeted treatment or treatment.