There are often patients with chronic fever who have gone through various hospitals without being able to identify the cause of the fever. Some of the patients with prolonged fever seen in our department are eventually diagnosed with lymphoma or other tumors, some of which develop into hemophagocytic syndrome; others are caused by various types of infections, such as bacterial, viral, fungal and malaria infections; and some are caused by autoimmune diseases. The febrile process is terminated after appropriate treatment of the above diseases. In clinical practice, there is also a small proportion of patients who cannot find a clear cause after various examinations, and who have long-term intermittent fever, which is ineffective after various treatments, and we attribute these fevers to immune disorders in the body. Usually, after immune balancing treatment in Chinese medicine, the fever gradually stops after 1-2 weeks of improvement. The mechanism needs further study.