Fever at night for several days in a row, normal during the day is mostly due to infectious factors, such as bacterial, viral or fungal infections, chronic fever, but also need to be vigilant about tuberculosis; also seen in non-infectious factors, such as malignant tumors, hyperthyroidism and so on. 1. Infectious factors, most of the fever is caused by infectious diseases, common bacterial, viral, fungal infections, tuberculosis, there will be fever at night, night sweats (abnormal sweating after going to sleep, waking up sweating stops), etc., no fever in the daytime, accompanied by fatigue, emaciation, etc., the diagnosis can be clarified by visiting the hospital. 2. Non-infectious factors, common malignant tumors in the late stage will cause fever, fever more irregular, accompanied by lethargy, fatigue and so on. It is also seen in hyperthyroidism, which is characterized by fever, emaciation and excessive sweating. If there are several consecutive days of fever at night, indicating that there is still an infection in the body, in the state of disease, must pay great attention to, timely to the hospital to carry out relevant examinations, a clear diagnosis and then targeted treatment.