Abstract:To retrospectively analyze onset ages, the causes and locations of gastrointestinal hemorrhage in children under 14 years old. The effects of different bleeding causes on red blood cells, hemoglobin and hematocrit in peripheral blood were further studied. Methods Data from 123 case children with gastrointestinal hemorrhage from January 2012 to September 2018 were summarized about the age of onset, clinical manifestation, etiology, bleeding site and red blood cells, hemoglobin, hematocrit in peripheral blood. Results Gastrointestinal bleeding in children is more common in preschool children. The manifestations mainly include hematemesis in 73 cases, bloody stool in 50 cases, abdominal pain in 17 cases. The endoscopic examination found upper gastrointestinal hemorrhage in 105 cases and gastrointestinal bleeding in 18 cases. The upper gastrointestinal hemorrhage was often caused by gastric ulcer 28 cases, hemorrhagic or erosive gastritis 27 cases and duodenal bulb ulcers 19 cases and so on. The bleeding site was usually seen in the stomach in 43 cases, the stomach sinus in 39 cases and the duodenal bulb in 16 cases. The causes of lower gastrointestinal hemorrhage were Meckel diverticulum in 7 cases, rectal colitis in 5 cases, and intestinal polyps in 4 cases. Bleeding site was seen in small intestine in 7 cases, rectum in 7 cases, sigmoid colon in 6 cases. The red blood cells, hemoglobin, and hematocrit in peripheral blood were affected obviously when bleeding caused by Duodenal bulbar ulcer, Meckel diverticulum, and varices in the stomach of the esophagus (P < 0.05). Conclusion The upper gastrointestinal hemorrhage is more common than lower gastrointestinal hemorrhage for children. The causes of upper gastrointestinal hemorrhage were gastric ulcer, hemorrhagic or erosive gastritis and duodenal bulbar ulcer. The most common causes of lower gastrointestinal hemorrhage are Meckel diverticulum, rectal colitis and colonic polyp, while the most common site of hemorrhage is small intestine, rectum and sigmoid colon. Duodenal bulbar ulcer, Meckel diverticulum, and esophageal varices leading to gastrointestinal hemorrhage are of great clinical harm to the children.