Abstract: This invention is an extracorporal thermo-therapy device having inlets and outlets being connected in shunt to a human body's blood vessel system, thereby providing the blood with a detour outside the body, thus becoming an integral part of the body's circulatory fluid system. The fluid system includes not only the blood itself but also all other body fluids (through the intra-corporal exchange between the blood and all other body fluids) for example the serum from the lymphatic system. The puropose of the invention is to use the process and device described to generate extracorporal fever in the blood to a level of around 2.degree. C. above normal body temperature everytime it is on said detour, thus activating the body's own immune system by stimulating the production of white blood cells and antibodies. If the device is used to generate extracorporal fever to a level of around 2.degree. C.