The invention relates to a method for hypothermia and rewarming of the cerebrospinal fluid in the brain. In one embodiment, cooling and rewarming of the cerebrospinal fluid is accomplished by applying cooling and rewarming elements externally placed in contact with the skin overlying the cerebrospinal fluid cisterns at the back of the head and spine regions of a patient. In another embodiment, hypothermia and rewarming is accomplished using a double barrel ventricular catheter placed within the lateral ventricles with one catheter used for heat exchange and the other for drainage of excess cerebrospinal fluid. In yet another embodiment of the invention, hypothermia and rewarming is accomplished using a loop catheter with fluid running through the loop placed in the lateral ventricles.