Coughing up blood is usually the middle or late stage of lung cancer, but it is not absolute and should be treated differently. 1. Typical symptoms of lung cancer in early stage are cough, chest pain, hoarseness, fever, etc. Generally, coughing up blood will not appear. However, if lung cancer patients are combined with bronchiectasis, chronic bronchitis, benign bronchial adenoma, non-specific ulceration of bronchial mucosa and other diseases, coughing up blood can be caused in the early stage. 2. In the middle and late stages of lung cancer, there are many symptoms of coughing up blood, or there is blood in sputum, or a small amount of blood is coughed up. This is mainly due to the fact that the tumor in the middle and late stages of lung cancer will invade the surrounding blood vessels, or the tumor rupture caused by repeated coughing. If lung cancer is diagnosed, it is recommended to reduce the adverse effects of the disease through “early detection, early diagnosis and early treatment”, and carry out regular treatment under the guidance of doctors.