To try to answer these questions, scientists searched the scientific literature, but found very little evidence to support prescribing paracetamol and ibuprofen, either in combination or alternately. They also found other important gaps in the evidence, including limited safety data and no clear definition of what is a clinically important temperature difference after treatment. Until such evidence is available, the role of combined anti-fever drugs is uncertain, they warn, and parents should be advised to use the minimum treatment necessary.