The most common cause of vomiting blood in the elderly is upper gastrointestinal bleeding, which is mainly caused by damage to the mucosa of the stomach, esophagus and duodenum. There are 3 main causes of bleeding: 1. Bleeding caused by lesions in the gastrointestinal tract itself, such as bleeding caused by mucosal erosion, ulcers and malignant tumors in the above 3 areas. 2. Bleeding caused by lesions in the gastrointestinal tract caused by other diseases, such as liver cancer or liver cirrhosis caused by Gastric fundic esophageal varices that cause bleeding. 3. Some hematological system diseases that cause coagulation disorders can also lead to gastrointestinal bleeding and the symptom of vomiting blood. In addition, blood vomiting should be distinguished from coughing up blood in the lungs or bleeding in the mouth.