Common cough refers to cough from cold, pharyngitis, bronchitis or pneumonia. Most coughs have causative factors, such as cold, exertion, rain or alcohol, and are accompanied by coughing sputum, fever and sore throat, etc. They improve quickly after treatment and do not leave any after-effects. Lung cancer cough has no causative factors, no history of cold or flu, and the cough is progressively aggravated. The so-called progressive aggravation is getting heavier and heavier, especially the prominent cough, which is a high-pitched metallic cough with a very loud sound. At the same time, lung cancer cough is accompanied by blood in sputum, and some patients have fever and chest pain when combined with infection. There is a difference between lung cancer cough and common cough, but there is no specific difference. If ordinary cough does not improve after treatment, it is necessary to go to hospital for examination and chest X-ray to exclude lung cancer disease or other diseases.