A vacuum motor and a lavage system comprising the vacuum motor. The vacuummotor comprises a working plunger linearly movable in an internal space, aresettingelement, a gas inlet opening for supplying ambient air or compressed gas intotheinternal space, and a gas outlet opening connected to a negative pressuresource fordischarging the gas from the internal space. A control plunger, which ismobile relativeto the working plunger, is arranged between the working plunger and a rearside of theinternal space. A catch element is arranged on the working plunger and/orcontrolplunger, whereby the catch element, upon a motion of the working plungertowards thefront side of the internal space, transfers the control plunger into a firstposition, andupon a motion of the working plunger towards the rear side of the internalspace,transfers the control plunger into a second position.
