A surgical tissue coagulator includes an elongate, biocompatible, flexible tube having an open distal end and a proximal end. The tube has an external diameter of less than about 5 mm, and is insertable into and maneuverable within a surgical endoscope. The proximal end of the tube is connectable with a source of argon gas so that a stream of the gas can flow through the tube and exit the distal end of the tube. A flexible wire is provided within the tube for conducting radiofrequency (RF) current. The wire has a distal end for positioning adjacent the distal end of the tube, and a tungsten tip is provided at the distal end of the wire for discharging an arc of RF energy away from the distal end of the wire within the stream of argon gas exiting the distal end of the tube. The wire has a proximal end opposite the distal end thereof. The wire is connectable at the proximal end thereof with a source of RF energy. A handle is attached to the tube adjacent the proximal end of the tube for maneuvering the tube within the endoscope while the handle is outside the endoscope. The process of the invention utilizes the surgical tissue coagulator defined above.