Coughing up blood in the throat is called hemoptysis in respiratory medicine, and its pathogenesis may be related to tuberculosis, bronchiectasis, lung cancer and other causes. 1. Tuberculosis: Tuberculosis is caused by Mycobacterium tuberculosis infection, which is an infectious disease, mainly manifested as cough, sputum, low-grade fever, chest tightness, etc., and sometimes hemoptysis in the throat. 2. Bronchial dilatation: bronchial dilatation is related to respiratory tract infection and inflammation, which will lead to repeated persistent cough and sputum, and most of the patients will also have the symptom of hemoptysis in the throat. 3. Lung cancer: the cause of lung cancer is still unclear, and it is related to ionizing radiation, bad dietary habits and heredity. There are no obvious symptoms in the early stage of the disease, but with the development of the disease, the symptom of hemoptysis in the throat may appear. The causes of hemoptysis in the throat are not only the above ones, but also the causes of lung cancer. You should consult doctor in time for systematic examination and diagnosis, and follow the doctor’s instruction to standardize the treatment.