To provide reliable holding of a closure tampon for incontinent natural anus or an artificial anus after colostomy, an elongated essentially cylindrical body of cellular material, for example similar to a catamenial tampon, is provided with non-homogeneous sections, taken in longitudinal direction, and having differential diametrical compressibility, so that a section of low compressibility can be inserted in the exit opening for internal expansion to thereby hold its position in the artificial anus, the section of high compressibility permitting constriction to provide, after insertion of the low-compressibility section first, a plug effect.