A self-opening closure, having: a tubular pouring spout, which defines a longitudinal axis and is provided on its inner side with an internal thread having a pitch angle (α), a cap, which upwardly covers the pouring spout and which, for the purpose of opening the closure, is rotatable in an opening direction and, for the purpose of re-closing the closure, is rotatable in a closing direction opposite to the opening direction, wherein the cap has at least one driver, which defines a front edge that runs inclined downward by a first angle of inclination (β) relative to the longitudinal axis; and a self-opening sleeve, which comprises a supporting ring, on which an external thread is provided, that engages in the internal thread of the pouring spout, and wherein the self-opening sleeve on its inner side has at least one driving cam, wherein the driving cam defines a guide face which, when the closure is opened for the first time, cooperates with the front edge of the driver in order to move the self-opening sleeve in the pouring spout in a screw-like manner downward out of an original position into an opening position, characterized in that the self-opening sleeve comprises exactly two teeth (22, 23), namely a first tooth, which extends downward protruding from the supporting ring, comprises a tip as well as defines a front cutting edge, and a second tooth, which also comprises a tip and, with respect to the opening direction, follows the first tooth at an angular distance of about 90°-180°, measured from tip to tip, wherein the second tooth extends downward with respect to the longitudinal axis as far as the first tooth, and wherein the self-opening sleeve has no further teeth, and that the guide face of the driving cam runs inclined by the same angle of inclination as the front edge of the driver relative to the longitudinal axis. a tubular pouring spout, which defines a longitudinal axis and is provided on its inner side with an internal thread having a pitch angle (α), a cap, which upwardly covers the pouring spout and which, for the purpose of opening the closure, is rotatable in an opening direction and, for the purpose of re-closing the closure, is rotatable in a closing direction opposite to the opening direction, wherein the cap has at least one driver, which defines a front edge that runs inclined downward by a first angle of inclination (β) relative to the longitudinal axis; and a self-opening sleeve, which comprises a supporting ring, on which an external thread is provided, that engages in the internal thread of the pouring spout, and wherein the self-opening sleeve on its inner side has at least one driving cam, wherein the driving cam defines a guide face which, when the closure is opened for the first time, cooperates with the front edge of the driver in order to move the self-opening sleeve in the pouring spout in a screw-like manner downward out of an original position into an opening position, characterized in that the self-opening sleeve comprises exactly two teeth (22, 23), namely a first tooth, which extends downward protruding from the supporting ring, comprises a tip as well as defines a front cutting edge, and a second tooth, which also comprises a tip and, with respect to the opening direction, follows the first tooth at an angular distance of about 90°-180°, measured from tip to tip, wherein the second tooth extends downward with respect to the longitudinal axis as far as the first tooth, and wherein the self-opening sleeve has no further teeth, and that the guide face of the driving cam runs inclined by the same angle of inclination as the front edge of the driver relative to the longitudinal axis.