There are many causes of fever, so the time required for recovery varies greatly; recovery can be as short as 2 to 3 days, or as long as the fever persists. Fever caused by some diseases is self-limiting and can be recovered more quickly, for example, the temperature of a mild case of common cold can return to normal within 2 to 3 days. Fever caused by some diseases can also return to normal quickly after active treatment, such as bacterial upper respiratory tract infection, bacterial pneumonia and other related diseases, if the treatment is effective, sometimes the temperature can drop significantly in about 3 days, or even return to normal. However, fever caused by some diseases may last for a longer period of time, for example, fever caused by pyothorax, without adequate chest drainage, the temperature can be prolonged. Fever caused by tuberculosis, for example, may continue without relief if no standardized anti-tuberculosis treatment is administered. Therefore, the time needed to recover from fever is related to the specific condition and whether the treatment is standardized and other factors, it is best to consult a doctor in time to identify the cause of the fever and follow the doctor’s instructions for treatment.