Abstract: The invention concerns a method of fragmenting and/or weakening of material by means of high voltage discharges. The material is together with a process liquid introduced into a process area, in which two electrodes face each other at a distance, and is arranged therein in such a manner that the area between the two electrodes is filled with material and process liquid. Between the two electrodes high voltage discharges are generated for fragmenting or weakening, respectively, of the material. According to the invention, during the fragmenting or weakening, respectively, of the material, process liquid is discharged from the process area and process liquid is fed into the process area. The process liquid which is fed has a lower electrical conductivity than the process liquid which is discharged.