In a method for operating a high-temperature fuel cell, which in normal mode of generating electrical power is supplied with liquid fuel, preferably diesel oil, and is preceded on the anode side by a reformer for liquid fuel, where at least part of the hot anode exhaust gas is recirculated into the anode circuit via a recirculation line. Upstream of a compressor preceding the reformer the liquid fuel is sprayed or injected into the hot anode exhaust gas, the quantity of air needed for reforming the liquid fuel being added to the mixture of anode exhaust gas and fuel. On change-over from normal operational mode to standby mode without power generation, the supply of liquid fuel and air is stopped and the gas mixture present in the anode circuit be permanently circulated. A defined amount of air being introduced into the anode circuit in order to remove deposits and contaminations in the high-temperature fuel cell following standby operation.