Usually, white foamy sputum is not an early symptom of lung cancer. The early symptoms of lung cancer are usually dry cough or little sputum, often manifested as irritating cough that cannot be controlled by medication, before gradually developing into persistent blood in sputum or even hemoptysis. Hemoptysis is coughing up fresh blood when coughing, and may be accompanied by chest pain and other symptoms between coughs. One of the types of lung cancer, alveolar cell carcinoma, can appear a large amount of mucus sputum when coughing, and the sputum volume is large and the texture is mucopurulent, which needs to be distinguished from white foamy sputum. Therefore, white foamy sputum is not a symptom of early lung cancer. Besides cough, lung cancer also has other typical symptoms, such as shortness of breath or wheezing. When lung cancer tumor compresses bronchial tubes, it causes obstruction of airway, which can lead to difficulty in breathing, wheezing and occasional wheezing sound. Necrotic tumor tissue can cause fever and this type of fever is not well treated with antibiotics. After the tumor continues to develop, it may show significant wasting due to tumor toxins and symptoms such as pain and infection. White foamy sputum is usually a manifestation caused by infection, such as pharyngitis, pneumonia, bronchitis, pulmonary edema, etc. Inflammatory factors stimulate the respiratory mucosa and alveolar cells, causing them to secrete fluid to protect the respiratory tract, resulting in white foamy sputum. If white foamy sputum appears, if other symptoms are mild, you can use some throat-clearing drugs, such as watermelon cream or licorice tablets; if accompanied by other symptoms are more serious, such as strong sore throat or even chest pain, it suggests that it may develop into pneumonia, and you need to go to a hospital for comprehensive treatment to avoid delaying the disease.