A medical instrument for treating, in particular for removing tissue, bone cement or the like in the human or animal body, comprising a hand piece having a distal end; an application part arranged at said distal end said hand piece, said application part being axially movable to-and-fro relative to said hand piece; a drive mechanism for said application part, said drive mechanism being provided in said hand piece, said drive mechanism transferring a pressure being continuously present in said hand piece into said to-and-fro movement of said application part, wherein said application part has at least in a region of a distal end of said application part a conduit, which has, in a distal region of said conduit, at least a suction and/or irrigation aperture.