A tampon suitable for feminine hygiene and/or medical purposes is disclosed having a longitudinal body provided with a dome-shaped insertion end and a withdrawal end, from which withdrawal end a withdrawal cord extends. The tampon has compressed absorbent fibrous material and has an outer circumferential surface which is at least partially provided with longitudinal grooves that are separated from each other by longitudinal ribs. The path of the grooves and ribs of the tampon in the longitudinal direction are inclined and correspond to a continuous curved line that has only one point of inflection defining one convex part and one concave part that preferably does not show a maximum or a minimum.