Gastrointestinal bleeding is bleeding from the esophagus, stomach, intestines, bile duct, pancreatic duct and other parts. Among them, bleeding from the esophagus, stomach, duodenum, bile duct, pancreatic duct and other parts above the Treitz ligament is upper gastrointestinal bleeding, and bleeding from the jejunum, ileum, colon, rectum and other parts below the Treitz ligament is lower gastrointestinal bleeding; jejunal bleeding after gastrojejunostomy is classified as upper gastrointestinal bleeding. Gastrointestinal bleeding has a high incidence and mortality rate in the elderly. It is easily masked by other diseases such as cardiovascular disease, and often becomes a diagnostic clue for other diseases such as tumors. In clinical practice, it is often necessary to take into account hemostasis treatment, complication treatment, primary disease treatment and treatment of concomitant lesions such as cardiovascular disease.