OBJECTIVE: To investigate the protective effects of mild hypothermia (33-35 degrees C) on the outcome of patients with severe traumatic brain injury (TBI) (GCS<8). METHODS: Patients in the mild hypothermia group were cooled to 33-35 degrees C by cooling blanket with muscular relaxant, and patients in the normothermia group were maintained at 37-38 degrees C. RESULTS: The result showed that the mortality was 26.1% (6/23) in the mild hypothermia group and 58.3% (14/24) in the normothermia group respectively (P<0.05). The mild hypothermia also markedly reduced intracranial pressure (P<0.01 and inhibited hyperglycermia (P<0.05). No significant side-effects were found during hypothermic treatment. CONCLUSIONS: Our clinical data have demonstrated that mild hypothermia is a useful method for management of patients with severe traumatic brain injury.