Ibuprofen does not reduce fever may be caused by insufficient oral dose, not reaching the time of onset of action, and the infection is still not controlled. 1. Insufficient oral dosage: you can carefully compare the dosage of ibuprofen with the instruction manual of the medicine, if the dosage of ibuprofen is insufficient, which will lead to the situation that ibuprofen does not reduce fever. 2. Not to the effect of time: after taking ibuprofen, it can be absorbed by the body to take effect, usually need half an hour to an hour of time, the body temperature will slowly come down. If you take ibuprofen less than half an hour, it is entirely possible that the fever does not go down, so this situation can also occur after taking ibuprofen does not reduce fever. 3. The infection is still not controlled: the main consideration may be due to the infection is not timely control, resulting in repeated fever or persistent high fever, thus appearing to take ibuprofen does not reduce the fever of the situation. If the patient takes ibuprofen does not reduce fever, it is recommended to go to the hospital in time, after a clear examination, according to the doctor’s guidance for the use of medication, do not buy their own medicine, so as not to cause adverse consequences.