Current concepts of fever *

Fever is a regulated re‐setting of body temperature, rather than a failure of control. Opinion has fluctuated for centuries between regarding it as a favourable response to disease or as an adverse effect. Some of the mechanisms of fever have been defined and thus the mode of action of antipyretic drugs can be explained. It has also become clear that fever has a longer evolutionary history than ‘warm bloodedness’, thus it is hard to imagine the perpetuation of such an ancient and widespread response unless its effects were beneficial. Only recently, however, has the nature of these benefits begun to be established.