Recent evidence indicates that the relationship between "brain protection" and the degree of hypothermia is not linear, and even mild reduction of body temperature (i.e. 2-5 degrees C) may provide protection against cerebral ischemia. The protective effects of mild hypothermia have been demonstrated in various animal models of cerebral ischemia, and are encouraging in human studies. At the present time, although there is no randomized clinical trial assessing the benefits of mild hypothermia for intracranial aneurysm clipping, some neurosurgical centers are routinely instituting mild hypothermia before vascular occlusion.