Abstract: An electromagnetic apparatus for treating patients. The apparatus comprises an electromagnetic frequency generator and a coil connected thereto for transmitting electromagnetic energy to a body part of a patient. A control connects to the electromagnetic frequency generator and to a number of sensors that register a local skin temperature and/or a skin resistance of the body part. The control contains an algorithm comprising an adjustment module and a treatment module. The adjustment module causes the transmission of electromagnetic energy of different test frequencies while recording with respect to each of the test frequencies corresponding variations observed by the sensors. The adjustment module is further arranged for determining a treatment frequency at which a significant variation is observed with at least one of the sensors.