Abstract: Electrosurgical instruments for the coagulation of biological tissue are known that comprise a gas source to supply an inert gas, in particular a noble gas, to at least one outflow opening as well as an HF source to supply a coagulation current to an electrode device that is disposed in the region of the at least one outflow opening. It is proposed to make the outflow opening slit-shaped in such a way that the inert gas emerges in a flat or fan-shaped stream, which in its marginal regions flows laminarly so that the inert gas reaches the tissue substantially without becoming mixed with ambient air.