1. An assembly for treating wounds having a device for generating a plasma and/or an excited gas or gas mixture, wherein the device comprises:a housing;
a piezoelectric transformer arranged in the housing;
a circuit board arranged in the housing, the circuit board including a control circuit, to which the piezoelectric transformer is electrically connected;
an opening formed in the housing towards which a high voltage end of the piezoelectric transformer is directed;
a fan arranged in or at the housing to provide a flow of air within the housing towards the opening, wherein the plasma and/or the excited gas or gas mixture, respectively, generated with the device exits from the opening; and,
an expansion element, including:
a first end removably connected to the housing at the opening; and,
a second end arranged to surround a wound region to be treated, wherein a cross-sectional area of the second end is larger than a cross-sectional area of the first end.