An electrosurgical apparatus for coagulating tissue used in combination with an endoscope which includes an elongated flexible tube having a plurality of side-ports located therethrough. The tube extends through a working channel of the endoscope and an ionizable gas is supplied to the tube at or near the proximal end of the tube. A diffusing member directs the ionizable gas from the proximal end of the tube through each of the side-ports towards the tissue. An electrode is used for ionizing the gas prior to the gas exiting the side-ports.