When the baby began to save belly can not be generalized, more with the baby’s development and feeding methods. Baby save belly is due to the digestive system continues to improve, gastrointestinal digestive enzymes continue to increase, intestinal peristalsis continues to increase, digestive function continues to become better, fully digested and absorbed milk food residue is less caused by. If the baby is well developed, save belly occurs in about 2 months after birth, and breastfed babies are the most common. However, if the infant is born with a deficiency, poor development, the belly may appear later. Therefore, the specific time of the baby’s belly varies from person to person, and after the occurrence of belly as long as the mental state is good, the stool is not dry, not bloated, no nausea and vomiting and other symptoms, there is no need to worry too much about it, and wait until the baby’s gastrointestinal function is further developed that would be improved on its own. In addition, if the baby continues not to defecate for more than three days, and even sleep instability, irritability and crying, nausea and vomiting and other manifestations, we should consider whether there is the possibility of constipation. If the constipation cannot be relieved by abdominal massage, increasing the amount of milk and drinking more water, then it is necessary to go to the pediatric gastroenterology department of the hospital in a timely manner.