Hematemesis and hematochezia are common symptoms of gastrointestinal bleeding in newborns. In general, gastrointestinal bleeding above the levator duodenum (also known as the Treitz ligament) is called upper gastrointestinal bleeding, which is mainly characterized by hematemesis, while lower gastrointestinal bleeding is mainly characterized by hematochezia. When the amount of bleeding in the lower gastrointestinal tract is large, or the pressure in the intestine is higher than the pressure in the stomach, bloody fluid can flow back into the stomach and esophagus, which can also cause hematemesis; conversely, when the amount of upper gastrointestinal bleeding exceeds 3 ml, black stools may also occur. That is, black stools may not be accompanied by hematemesis, but black stools are often accompanied by hematemesis.