Hyperthermia is an ancient, but nowadays rapidly developing treatment method in tumor-therapy. Its new paradigm applied in the electro-hyperthermia (oncothermia), which provides energy by means of electric-field and produces non-equilibrium thermal situation in the tissue. The temperature gradients formed in stationary conditions, destroy the membrane of the malignant cells and selectively eliminate the cancer tissue. The characteristic control parameter is the absorbed energy-dose, which is partly used to make the distortions, partly to increase the temperature of the target. This type of technique could be applied for some tumor sites, including brain, soft tissues, liver and abdominal masses, pancreatic cancer, head and neck tumors as well.