The fever usually lasts 1 to 2 days in the case of upper respiratory tract infections and 3 days or more in the case of lower respiratory tract infections such as lung infections. If the fever is caused by upper respiratory tract infection, it is a normal manifestation of viral infection. If the temperature is below 38.5°C, physical cooling is used, including warm water baths. If the temperature exceeds 38.5°C, antipyretic drugs such as acetaminophen are usually used symptomatically to reduce fever within a few hours. After 1 to 2 days the temperature can be completely controlled and the fever will no longer be present. However, if the fever is caused by lower respiratory tract infections such as lung infections, in addition to symptomatic antipyretic treatment, it is also necessary to choose the appropriate medication to control the infection according to the type of infection. It usually takes 3 days for the body temperature to return to normal. Some people with drug-resistant conditions may need a longer period of time. It is recommended to seek timely medical advice, subject to the doctor’s opinion, and at the same time follow the doctor’s instructions for medication.