The persistence of fever in children can be attributed to disease-related factors (e.g., acute stage of the disease), failure to use antipyretics appropriately, or failure to observe for a long period of time after the use of antipyretics. 1. Disease-related factors: in the acute phase of certain diseases, such as influenza children, there may be a persistent fever, the need for close observation, dynamic temperature monitoring, the rational use of ibuprofen and other antipyretic drugs. It can also be seen in some critical illnesses, such as sepsis, the above phenomenon can occur. 2. Failure to use antipyretics: ibuprofen or acetaminophen is often used in pediatrics for symptomatic antipyretic, which should be used according to the weight of the child under the guidance of the physician, and if it is used inappropriately, the antipyretic effect may be unsatisfactory, and the phenomenon of persistent fever may occur. 3. The observation time after using antipyretics is not enough: for children with fever, generally 30 minutes to 1 hour after using antipyretics, the temperature can gradually decline, some children in the acute stage of the disease can be 2~3 hours after using drugs to gradually decline, such as the observation time is not enough to appear the above phenomenon. Children with persistent fever, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.