Therapy with high-frequency alternating currents is primarily an application that very effectively generates heat in water-rich, ion-rich, and therefore electrically well-conductive tissue to a depth of about 5 cm, resulting in effects such as improved blood circulation, pain relief, and increased extensibility. Electromagnetic waves probably also have non-thermal effects, but these are difficult to demonstrate. In order for the aforementioned effects to occur, a certain tissue temperature must be reached. Based on the limited available literature, it is possible to provide approximate information on dosage. The risks associated with the application are discussed in detail.