Spitting out blood can be seen in the following diseases: First, lung tumor, patients with lung tumor can cough and have blood in sputum, which can be accompanied by other symptoms such as emaciation, chest pain, fatigue and so on. Secondly, tuberculosis, patients with tuberculosis may vomit blood, and may be accompanied by low fever in the afternoon, night sweating, mental depression and other symptoms. Third, lung infection, lung infection patients, often chills, fever, coughing, coughing up sputum and other symptoms, some patients can also be accompanied by spitting blood. Fourth, bronchial dilatation, bronchial dilatation patients can vomit blood, often cough, cough sputum and other symptoms, can also be accompanied by a large number of hemoptysis. In short, if you vomit blood, you should go to the hospital to take a chest X-ray, or do chest CT and other tests to further clarify the cause of the disease.