A hydraulics unit for an internal combustion engine with a hydraulically variable gas exchange valve gear, is provided that includes a hydraulic housing having a pressure chamber, a pressure relief chamber and a venting duct. The venting duct is connected, on a hydraulic housing inner side, to the pressure relief chamber via a restriction and opens on a hydraulic housing outer side. The venting duct has a siphon with a downward first duct section and an upward second duct section, respectively in the direction of gravity and in the venting direction. When a gas exchange valve is closed, a lowermost section of the siphon is below a boundary of a pressure chamber defined by a slave piston.