If a patient vomits black fluid, the possibility of upper gastrointestinal bleeding is mostly considered. As long as black fluid from eating is clearly excluded, it indicates the presence of upper gastrointestinal bleeding, which is quite serious. In most cases, upper gastrointestinal bleeding will manifest as black stools, and vomiting of blood rarely occurs. Only when the bleeding is very heavy and urgent will it manifest itself as vomiting of blood. If vomiting of blood occurs, it is likely to cause hemorrhagic shock and lead to the patient’s death. It is recommended that the patient needs to go to the hospital immediately and cooperate with the doctor for treatment. He needs to be admitted directly to the hospital, and the intravenous infusion channel should be opened immediately to replenish fluids while doing relevant tests. Blood transfusion and electrogastroscopy are needed to help clarify the cause and, if necessary, to perform microscopic hemostasis.