If you take ibuprofen to reduce fever and do not eat and then have a fever, it means that the primary disease that caused the fever has not been effectively controlled. 1. Fever is a clinical manifestation of the disease development process, if the fever is only reduced and the primary disease is not effectively treated, even after taking ibuprofen when the blood concentration is lower than the effective therapeutic amount, the fever will occur again. 2. The most important point of treatment is to find the primary disease that causes fever and treat the primary disease, with the effective treatment of the primary disease, the recurrent fever will gradually improve. Recurrent fever should be promptly consulted, the doctor to make a clear diagnosis, the doctor to make targeted treatment.