A pump module with a casing having at least one pump piston is mounted in a reciprocatingly movable manner and may include a sealing element which, in pumping operation, abuts in a sealing manner against a cylinder. An embodiment of a pump module, which is easy to produce and can be disinfected or sterilized in a simple manner, includes a pump piston that can be fixated in a parking position in which the sealing element does not abut against the cylinder.