A method for producing a balloon from a suitable blank is provided. The blank is introduced into an outer mold heated an first expanded to expand it against the inner wall of the outer mold. Pressure is reduced to relax the blank away from the inner wall. The three-dimensional volume of the mold is changed. Second expanding of the blank expands again against the inner wall of the changed volume of the outer mold. Balloons of the invention consist of a middle cylindrical region and two end regions delimiting the middle cylindrical region. With a pressure application of 6 bar, a ratio of the cross section in the middle region to the cross section in the end region is at least 2, and preferably greater than 3.