The favorable effect of hypothermia on brain damage resulting from cardiac arrest was first demonstrated in animal studies. Subsequent small-scale human studies have also shown positive effects. In 2002, two large randomized studies investigating the use of controlled mild hypothermia after resuscitation were published in the New England Journal of Medicine. The results convincingly showed a positive effect on survival and neurologic outcome. Based on the currently available data, the International Liaison Committee on Resuscitation (ILCOR) strongly recommends that unconscious adult patients who are resuscitated after ventricular fibrillation be cooled to temperatures between 32 and 34 degrees C for 12-24 h.