The sudden appearance of bloody sputum may be caused by acute inflammation of the throat or inflammation of the bronchial tubes, which needs to be actively treated with drugs to clear heat and remove fire and drugs to relieve cough and phlegm. In more serious cases, it is also necessary to treat with effective antibacterial drugs, and can also be appropriately treated with vitamin C for comprehensive treatment. If you have had cough and sputum before, you also need to consider that it is caused by bronchiectasis, chronic bronchitis, tuberculosis, and lung tumors. Mitral stenosis, congenital heart disease, and various acute infectious and blood disorders may also cause these symptoms and need to be examined in the hospital first. The main thing is that once the symptoms of coughing up blood are still relatively serious, you need to make a correct diagnosis based on the examination results and other clinical manifestations, and actively treat with medication under the guidance of a doctor.