Fever in an 11 year old child is commonly due to the invasion of pathogens. Common pathogens include viruses, bacteria, mycoplasma, chlamydia, and rickettsia. The pathogens undergo an inflammatory reaction in the child’s body, resulting in an increase in the child’s body temperature. If the child’s body temperature is less than 38.5 ℃, is a low fever, you can temporarily do not use antipyretic, drink more warm boiled water, fruit juice, through sweating and urination, take away the child’s body heat and reduce body temperature. If the body temperature is greater than 38.5 ℃, appropriate to take antipyretics. Such as acetaminophen or ibuprofen, test blood routine, clarify the cause of the disease, symptomatic treatment.