A device for the implantation of electrolytically severable occluding spirals in body cavities or blood vessels comprising a source of electrical power, a cathode, a catheter and an occluding spiral adapted to serve as an anode and able to slide in the catheter in the longitudinal direction, wherein the occluding spiral (3) is designed to be electrolytically corrodible at several spaced apart points so that when in contact with a body fluid one or more variably dimensioned lengths of the occluding spiral (3) may be severed by electrolysis.
