Black vomit and general weakness is considered to be related to upper gastrointestinal bleeding, eating certain foods with gastrointestinal diseases. 1. Upper gastrointestinal bleeding: mainly stomach and duodenum due to mucosal ulcers, erosion and other factors can cause bleeding, blood stays in the stomach will be digested by gastric acid, so the vomit out of the black material, vomiting can be accompanied by weakness, abdominal pain and other symptoms. 2. With eating food and gastrointestinal diseases: generally eat animal offal, blood products and bismuth, etc., which in the stomach and stomach acid mixing can appear when the vomiting of black gastric contents of the situation, vomiting can be due to gastrointestinal diseases, such as gastritis, gastric ulcers, gastrointestinal dysfunction and other factors caused by the vomiting can be accompanied by abdominal pain, acid reflux, generalized weakness, and other discomforts. The causes of vomiting black material and general weakness are gastric cancer, cardia mucous membrane tear, etc. It is necessary to go to the hospital as soon as possible to find out the cause of the disease under the guidance of the doctor to avoid delaying the condition.