The application of antipyretic drugs after fever usually requires observation for 4 hours. After taking antipyretic drugs, if the body temperature does not return, you should continue to observe and not take antipyretic drugs again immediately to avoid increasing the side effects of the drugs and increasing the burden on the liver and kidneys. Sometimes the body temperature does not come down immediately after the application of antipyretic drugs. This is because the reduction of body temperature needs to be accomplished through the body’s heat dissipation, which is often achieved through the sweat holes on the surface of the skin and urine discharge to achieve the effect of cooling. If the body does not take in enough fluid, antipyretic drugs will not work as well as they should. For some patients with infections, such as purulent tonsillitis, the withdrawal effect may not be particularly obvious after the application of antipyretic drugs, because the infection in the body is not effectively controlled, in addition to the effective antipyretic need to take antibiotics to control the infection. When the infection is controlled, the body temperature will return to normal. Some patients with fever that does not subside may not find the root cause, such as some patients with tuberculosis and tumors, and blindly use antipyretic drugs, the effect is not good. Therefore, the fever does not subside is related to the antipyretic drugs used on the one hand, and the fluid intake on the other hand. In addition, it is necessary to identify the specific cause of the disease and treat the cause in order to solve the problem at all.