Abstract: A drainage catheter comprises a tubular basic catheter body defining separate catheter lumens respectively comprising a pressure channel and a discharge channel. Connectors are provided at the proximal end of the catheter for respectively connecting the pressure channel to a source of liquid under pressure and the discharge channel to a discharge receptacle. An inlet opening is positioned in the side of the catheter adjacent the distal end thereof. The discharge channel communicates with the inlet opening, while the pressure channel extends from the proximal and distally forward of the inlet opening and then curves rearwardly to join the discharge channel at the inlet opening. In one embodiment of this invention the pressure channel defines a distal portion that is of rigid and fixed dimension to define a spray nozzle of precise, unchanging dimensions.