Abdominal distension can be caused by the accumulation of gas and fluid in the intestinal cavity and abdominal cavity, huge intra-abdominal masses or weakness of the abdominal muscles, pediatric abdominal distension is most common with gas distension, which is commonly known as “flatulence”. The general intestinal gas mainly comes from the gas swallowed and the gas produced in the digestive tract. Under normal circumstances, children over 2 years old and adults, in addition to the stomach and colon, there is no gas in the small intestine, while the normal small intestine of newborns should be inflated, no gas is mostly pathological phenomena, especially after a full stomach expansion, often higher than the glabella, the abdomen is empty when hungry. Abdominal distension is considered when the abdomen of a newborn is found to be continuously inflated and not deflated, and there is tension. The child also has an acute or chronic illness, and small infants may have crying, abdominal bulge high out of the chest, and severe abdominal distension may affect breathing and cannot lie down. If you tap on the abdomen at this time, you can hear a sound similar to that of a drum. Gas and distension can be divided into two cases, generally gastrointestinal distension, but there are a few is pneumoperitoneum. Tap the abdomen, if you feel more empty and soft for pneumoperitoneum, and intestinal distension can be felt in the shape of intestines. If parents are not good at differentiating and the child cries significantly, they should promptly visit the hospital to check for subdiaphragmatic pneumatosis by standing x-ray.