4-month-old babies will have indigestion because of the following reasons: 1, 4-month-old babies intestinal micro-ecosystem itself is not established soundly, prone to intestinal micro-ecological imbalance, especially in the state of disease is more prone to occur. 2, 4-month-old babies may have milk protein allergy, breastfed babies are also related to the mother’s diet, the mother ingested the baby easy to be allergic to the Foods will cause the infant to develop intestinal symptoms, resulting in indigestion.3, some children have insufficient or relative lack of lactase activity, or may be secondary to lactose intolerance caused by intestinal viral infections, which is prone to indigestion.4, 4-month-old infants have low immunity and poor resistance, and are susceptible to pathogens such as intestinal viral infections or bacterial infections that can cause a decrease in digestive function and thus Indigestion occurs.