Spiral implant for organ pathways, in particular for blood vessels, which is formed from a primary spiral made of metal or a primary tube made of an elastic synthetic material whose anterior end is closed and whose cross-section at a distance of 0.5 to 2 mm from the other end of the primary spiral or primary tube is modified for a distance of 0.01 to 10 mm in order to make it possible to reposition the implant. The force required to displace the primary shape on the guide wire serving as an insertion aid amounts to 0.5N to 10N. The invention describes an implant (1) which can be used in vascular surgery or vascular radiology in order to achieve selective blood vessel occlusion. Insertion of the implant (1) into a blood vessel is brought about by means of an insertion catheter (16), with the implant being held in a rectilinear shape by a guide wire (14) slid therein. After the implant has reached the correct position in the organ pathway (18) it assumes a pre-formed spiral shape on the withdrawal of the insertion wire from inside it, thereby ensuring fixation of the implant in the organ pathway.