The invention relates to a catheter for introducing into a hollow human or animal organ. Said catheter comprises a catheter tip that protrudes forwards and a region that is encased by an expandable tubular hollow body and that is situated behind the catheter tip. Said catheter is characterised in that a wire spiral is located in the encased region. It can also be advantageous to provide a radiopaque ring, in particular a platinum, gold or tungsten ring, on a hollow shaft of the catheter, together with several rib-type projections running around the hollow shaft and projecting from the latter, in a region in front of and/or behind the radiopaque ring.