Lung cancer with sputum after chemotherapy is considered to be the side effect of drugs or the formation of infectious disease in lung, it is suggested to clarify the cause of the disease and then treat the cause. 1. Some lung cancer patients may have excessive sputum in the process of chemotherapy, which is a side effect of drugs, they can apply symptomatic drugs to improve the symptoms under the guidance of doctors, and it is not recommended to change the program if the chemotherapy program is effective. 2. During chemotherapy, patients’ resistance and immunity are low, and they are prone to bacterial infections and increased sputum. It is recommended to take antibiotics such as penicillin and doxycycline to control inflammation, and expectorant drugs such as bromhexine and aminoglutethimide to promote sputum discharge if necessary. Due to the diversity of causes and individual differences, there is no absolute safest and most effective drug, need to follow the doctor’s instructions to standardize the use of adverse reactions recommend medical treatment, drug allergy is prohibited.