There is no fixed time for how long it takes for cough to get better after chemotherapy. Cough after chemotherapy may be caused by bacterial infection in lungs, which may get better in one or two weeks after whitening and anti-bacterial treatment. Cough after chemotherapy may also be caused by tumors, such as cough caused by the progression of lung cancer which is not good to chemotherapy, and it is necessary to change the treatment plan, and the cough may take several months or longer time to get better. 1. Cough caused by infection: chemotherapy can cause lowering of white blood cells, which can lead to cough caused by bacterial infection in lungs, in this case, timely treatment of white blood cells can be carried out, and at the same time, sputum culture and drug sensitivity test should be perfected to look for causative organisms and sensitive antibiotics, and the cough can be improved in one or two weeks’ time after active treatment. 2. Tumor-induced cough: tumor itself (lung cancer, lung metastasis) can cause cough, if the effect of chemotherapy is not good, the tumor can not be effectively controlled, chemotherapy can lead to cough, at this time, cough and chemotherapy has little to do with the disease progression caused by the need to change the chemotherapy regimen or treatment, cough may take several months or longer time to improve. So there is no fixed time for how long it takes for the cough to get better after chemotherapy, it needs to be analyzed on a case-by-case basis and cannot be generalized, it is recommended that the patient under the guidance of the doctor to carry out a detailed assessment and treatment.