Sputum with blood can be distinguished from the throat or lungs in the following ways: a. If the cough is not deep and is accompanied by a dry and itchy throat, coughing with blood in the sputum is generally considered to be caused by inflammation in the throat area. The amount of bleeding is usually less at this time, and it is easier to stop bleeding, and there is no obvious bleeding after gargling. Second, bleeding in sputum caused by lung diseases, mostly caused by bronchial dilatation, tuberculosis, lung cancer, pneumonia and other diseases, these blood in sputum is usually with blood clots, and the bleeding is not easy to stop, accompanied by chest tightness, shortness of breath, chest pain, fever and other symptoms, in addition, examination of chest CT can be a clear diagnosis.