A device for devitalizing biological tissue and a method for controlling a device for devitalizing biological tissue. According to one embodiment, at the start of the devitalization, a low, first temperature is used and, at the end of the devitalization, an increased, second temperature is used. A device and method for operating a cooled HF (high frequency) ablation probe, wherein the temperature of the probe is primarily regulated via the cooling power supplied to the probe, is also described. According to another embodiment, the HF energy supply to the probe during treatment of a tissue region is operated first at a constant current and then at a constant voltage. According to another embodiment, the regulation of the cooling power is carried out depending on the impedance of the tissue region.
