Noninvasive system for rising or lowering a patients 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).
