Exhaust gas systems of internal combustion engines, comprising: a flow housing (12) having a flow channel (34), by means of which an inlet (28) of the flow housing (12) is connected to a first outlet (36) and to a second outlet (44), which second outlet leads into an exhaust gas recirculation line (46), and comprising a cylinder head (10) having a first exhaust gas channel (30), which is directly connected to the inlet (28) of the flow housing (12), and having a second exhaust gas channel (38), which is fluidically connected to an exhaust gas outlet channel (22) and into which the first outlet (36) of the flow housing (12) leads, are known. The aim of the invention is to be able to control the recirculated exhaust gas flow in a simple way and to ensure particularly simple assembly. This aim is achieved, according to the invention, in that a first flap (48) is rotatably arranged in the flow channel (34), which first flap is arranged fluidically between the inlet (28) and the first outlet (36) or between the inlet (28) and the second outlet (44) in the flow channel (34) and can be moved by means of an actuator (70).