Eleven-month-old baby boy took ibuprofen after fever, the temperature retreated to 37.5 ℃, which means that the fever is not completely retreated, can not be called normal or abnormal. The causes of fever are very many, divided into infectious fever and non-infectious fever. Infectious fever includes fever caused by bacteria, virus, mycoplasma, chlamydia and so on. Non-infectious fever, including temperature regulation center abnormalities and some autoimmune diseases caused by fever. The most important role of ibuprofen as a fever-reducing drug is symptomatic treatment, that is, to temporarily help feverish babies lower their body temperature, in order to avoid the harm of high body temperature on the child. But it does not address the real cause behind the fever. So after using ibuprofen to reduce fever, the body temperature will drop temporarily, some children can’t come down to normal temperature, some children can come down to normal, but these can’t represent the improvement of the child’s condition itself. Therefore, it is recommended to seek medical attention to find the cause behind the fever and then provide targeted treatment according to the cause.