The last several years have seen an increased interest in the use of induced hypothermia after witnessed cardiopulmonary resuscitation (CPR). The main reason for its use is protection of the brain and hence, better neurological outcome in these patients. Therefore, induced hypothermia after CPR has become a part of standard recommendations in the 2005 Resuscitation Guidelines. At the same time, hypothermia can have many adverse effects. In the event of pre-hospital and/or in-hospital induction of hypothermia, without adequate monitoring and controlled cooling, hypothermia can cause serious complications, without beneficial effects on the brain. This article explains the most frequent adverse effects of hypothermia and possible hazardous outcomes for patients.