To cool or not to cool. Traumatic brain injury is a major cause of mortality and long term morbidity. Hypothermia has been suggested as a potential treatment to limit secondary brain injury and improve outcomes. However, this currently remains controversial. Despite many small studies and meta-analyses suggesting benefit this has not been reflected in the recent larger studies. This may have been due to significant methodological limitations. The Eurotheum study completed last year which examine hypothermia as a rescue therapy suggested that we should abandon hypothermia in our traumatically brain injured patients. Before our community discards this potentially beneficial treatment after almost 50 years of investigation it is important to understand the limitations of the previous studies and the opportunities that currently ongoing studies have to address this question.