Enlarged lymph nodes and recurrent daily fever are considered to be possibly caused by infection or tumor. Lymph nodes are peripheral lymphatic organs with relatively concentrated groups of lymph nodes in several superficial parts of the body and deep tissues. Lymph nodes are important immune organs and defense barriers in the human body, and can be stimulated by various pathogenic microbial infections, tumors and other factors, causing lymphocyte hyperplasia and resulting in lymph node enlargement. Pathogenic microorganisms such as viruses, bacteria, fungi, Mycobacterium tuberculosis, mycoplasma or chlamydia, parasites and so on. When the organism is infected, it will cause local or systemic inflammatory reaction, stimulate lymphocyte proliferation, and when the infection is severe, it can also cause lymph node necrosis and abscess formation, leading to lymph node enlargement. After infection, inflammatory factors or toxins are released into the blood, causing fever symptoms. Tumors include lymphatic system tumors and other tumors. Lymphatic system tumors include lymphoma, lymphocytic leukemia, and others. Tumors can invade lymph nodes, resulting in lymph node enlargement, and cause a febrile response after tumor necrosis factor enters the blood. When malignant tumors from other parts of the body metastasize to the lymph nodes, metastatic carcinoma is formed, which also causes lymph node enlargement and fever. Certain immune diseases can also cause lymph node enlargement with fever, such as systemic lupus erythematosus. When lymph node enlargement with fever occurs, it is recommended to consult a doctor in time, complete the examination, make a clear diagnosis, and follow the doctor’s instruction to carry out standardized treatment.