Generally, the reason of recurrent fever after radiotherapy for lung cancer may be esophagitis and infection caused by radiotherapy. Radiotherapy is the use of high-energy rays to kill tumor cells, which is one of the main treatment methods for lung cancer. After radiotherapy, it can lead to esophagitis, tracheitis, pneumonia and other side effects. At this time, it can lead to the symptom of fever in patients. It can be relieved by drinking more water, eating semi-fluid food, etc. If necessary, use antipyretic drugs under the guidance of physicians, or hormones such as dexamethasone + antibiotics for anti-inflammatory treatment. In addition, due to the development of the tumor and the side effects of the treatment can lead to the patient’s low immunity, which is prone to infection. This in turn leads to the symptom of fever. It can be treated by taking antibiotics such as penicillin under doctor’s instruction. Lung cancer tumor belongs to high consumption disease, which itself can also lead to fever, at this time, anti-tumor treatment should be carried out in time, such as surgery, chemotherapy and so on. It is suggested that if patients have recurrent fever, they should take CT, blood routine, inflammation index and other examinations under the guidance of doctors to clarify the cause of fever and carry out relevant treatment, and do not use medicines randomly on their own.