Abstract: The present invention relates to a method and device for the selective destruction of cells that with uncontrolled proliferation in an animal organism, with minimum damage to the surrounding tissue thereby and without needing to perform any kind of surgical operation on the patient: the method consists of the detection of the tumorous area (1) and the sequential and alternate application of at least two alternating magnetic fields with different directions to the treatment area or application until achieving the heating and destruction of the cells. The device used is, therefore, comprised of at least two electromagnets (11, 12) or at least two pairs of electromagnets (11-11?, 12-12?) all being located around the perimeter of a hypothetical circumference or sphere, with the electromagnets in opposing pairs where each opposing pair generates an electromagnetic field in one direction and orientation.