After the application of fever-reducing drugs can generally last 4-6 hours, but the half-life of each drug is different, for example, Merrill Lynch is about half a day, if some infections are more serious, the application of fever-reducing drugs need to increase the dose, and need to be used more frequently. Others only show mild fever, after the application of antipyretic drugs usually 12-24h will not recur fever symptoms, this situation and the body’s resistance has a certain relationship. Therefore, the application of antipyretic drugs must be combined with individual differences in the use of drugs, regular measurement of body temperature, if the temperature does not exceed 38.5 ℃ do not need to repeat the application.