An apparatus for a three-stage cooling and scrubbing system for the treatment of hot crude gases and liquid slag downstream of an entrained flow gasification. Crude gas and slag are firstly cooled and prescrubbed in a first stage by injection of water from ring and/or wall nozzles into a free quench space. Crude gas and slag are then fed together with excess water into a waterbath as a second stage before intensive spraying is once again carried out as a third cooling and scrubbing stage in an annular space.