A multifunctional instrument for HF surgical treatment of tissue, in particular for optional cutting, injecting and coagulating tissue is proposed. The multifunctional instrument has the following elements: at least one fluid chamber for receiving a fluid a temperature control device communicating with said at least one fluid chamber for warming, heating or evaporating a fluid present in said fluid chamber a temperature controller for controlling the temperature of the fluid present in the said fluid chamber, and at least one fluid outlet port arranged at a distal end of the multifunctional instrument and communicating with the said at least one fluid chamber.