Abstract: Noninvasive system for rising or lowering a patient's body temperature in a controlled manner comprising: a) a cervical blanket (1) with ducts (2) through which a fluid circulates (3); b) a fluid (3) capable of transferring heat from and to external bodies; c) a heat exchanger (4) which rises or lowers the fluid temperature that circulates through cervical blanket ducts; d) means of connection (5) between ducts (2) of the cervical blanket (1) an the heat exchanger (4); e) a body temperature sensor (6); f) a controller (7) which rises or lowers fluid temperature according to a predetermined temperature and according to the temperature measured by the body temperature sensor (6).