It may be caused by inflammatory diseases or autoimmune diseases, and needs to be diagnosed and treated accordingly. Clinically, chronic hypothermia can be caused by many kinds of cancer, such as acute leukemia, lymphoma, lung cancer, etc. It is usually caused by inflammation when the tumor is growing, or the tumor necrotic tissue is absorbed by the body leading to cancer fever. Patients need to be diagnosed clearly through pathological examination, bone marrow examination, CT or MRI, and then given surgery, radiotherapy, chemotherapy and other treatments. Other diseases, such as bronchitis, pneumonia, tuberculosis infection, Hashimoto’s thyroiditis, systemic lupus erythematosus, rheumatoid arthritis, etc., may also cause prolonged hypothermia. Therefore, for prolonged hypothermia, patients need to actively visit the department of infection, internal medicine or oncology for a comprehensive examination to clarify the cause of hypothermia. In daily life, patients should also eat a light diet, consume more nutritious food, drink more water, get enough sleep, and perform appropriate exercises to improve the immunity of the body.