Disclosed is a method for dressing a single- or multi-thread grinding worm (34) in which a main rolling movement between the grinding worm and a gear-like dressing tool (90) is brought about. In order to create flank modifications on the grinding worm, an additional relative movement is superimposed on the main rolling movement. In addition, an auxiliary drive specifically designed for such a method, a correspondingly designed machine tool and a dressing tool for carrying out the method are disclosed.