Abstract: Method and device for disintegrating concretions, or sclerotic clots within human ducts. The method and system are particularly adapted to disintegrating stones in the ureter and kidney, as well as the bladder. The method includes axially abutting the concretion within the human duct while outwardly distending the walls of the duct adjacent the concretion, directing a series of high voltage, low amperage pulses into the ducts and discharging the pulses radially outwardly across the surface of the concretions, while flowing a liquid peripherally of the discharging pulses, so as to direct an hydroelectric impact against the concretion. The outward distending of the walls and the flowing liquid, particularly in narrow human ducts such as the ureter, prevent tissue damage by shock and burning.