Coughing up bloody sputum from cold is not necessarily an early manifestation of cancer. Coughing up bloody sputum from cold is common in respiratory diseases, but some patients in the early stage of lung cancer may also show coughing up bloody sputum and symptoms similar to cold. After a cold, it will easily cause congestion and edema in the throat, which will lead to swelling and pain in the throat and cause coughing symptoms. If repeated coughing causes rupture of the capillaries in the local mucosa, bleeding may occur. When blood is coughed out together with sputum, it is manifested as bloody sputum. In addition, coughing up blood and blood in sputum are also common first symptoms of central lung cancer. When the tumor invades blood vessels, it will lead to the phenomenon of local bleeding, which is manifested as coughing up bloody sputum. In addition to bloody sputum, patients may also have fever, irritating dry cough, shortness of breath and other symptoms. When the symptoms of cold and coughing bloody sputum appear, most patients will get better through active treatment. If the amount of bleeding is relatively large and lasts for more than a week, it is necessary to go to the hospital for routine blood tests, chest X-ray or lung CT.