The invention relates to a method for fragmenting and/or weakening material by means of high-voltage pulses, the material and a processing fluid being arranged in a processing zone formed between two electrodes such that the entire processing zone is flooded with processing fluid, and high-voltage pulses being applied to the electrodes such that high-voltage breakdowns occur between the two electrodes and/or such that predischarge channels are formed without breakdowns. An electrode with a metallic conductor is chosen for at least one of the two electrodes, the conductor being provided partially or completely with an insulator or insulating coating at the working end of the electrode that is in contact with the processing fluid, the permittivity of the insulator/insulating coating being at least 75% of the permittivity of the processing fluid.