A device for sealing the mouth of a bottle, wherein the device comprises: (i) a plug including two cylindrical parts (3, 4) extending in the continuation of each other according to a longitudinal axis, forming a plug body and a plug head, respectively, wherein the plug head has a diameter that is higher than the diameter of said plug body, and wherein the plug head includes - a lower surface, connected to said plug body and - a free upper surface, located opposite said lower surface according to said longitudinal axis, and (ii) a tubular cap having a longitudinal axis and within which said plug is intended to be coaxially received, wherein the cap includes two parts (6, 7) extending in the continuation of each other according to said longitudinal axis, forming - a skirt, intended to extend opposite and remote from said plug body, including means for its locking in translation on said bottle, and - a membrane seal, intended to cover said plug head, respectively, and in which (iii) said plug head and said membrane seal include cam means (17, 32) that cooperate with each other to cause, upon a rotational operation of said membrane seal with respect to said plug head about said longitudinal axes (2', 5'), a translational movement of said membrane seal with respect to said plug head according to said longitudinal axes (2', 5') and in a direction oriented from the lower surface to the upper surface of said plug head, so that, once said sealing device added on the mouth of the bottle, characterized in that said membrane seal and said tubular skirt are fastened to each other by linking means including fracture initiation areas (8 a), and in that said manual operation in rotation of said membrane seal of the cap causes the degradation of said linking means. (i) a plug including two cylindrical parts (3, 4) extending in the continuation of each other according to a longitudinal axis, forming a plug body and a plug head, respectively, wherein the plug head has a diameter that is higher than the diameter of said plug body, and wherein the plug head includes - a lower surface, connected to said plug body and - a free upper surface, located opposite said lower surface according to said longitudinal axis, and (ii) a tubular cap having a longitudinal axis and within which said plug is intended to be coaxially received, wherein the cap includes two parts (6, 7) extending in the continuation of each other according to said longitudinal axis, forming - a skirt, intended to extend opposite and remote from said plug body, including means for its locking in translation on said bottle, and - a membrane seal, intended to cover said plug head, respectively, and in which (iii) said plug head and said membrane seal include cam means (17, 32) that cooperate with each other to cause, upon a rotational operation of said membrane seal with respect to said plug head about said longitudinal axes (2', 5'), a translational movement of said membrane seal with respect to said plug head according to said longitudinal axes (2', 5') and in a direction oriented from the lower surface to the upper surface of said plug head, so that, once said sealing device added on the mouth of the bottle, characterized in that said membrane seal and said tubular skirt are fastened to each other by linking means including fracture initiation areas (8 a), and in that said manual operation in rotation of said membrane seal of the cap causes the degradation of said linking means.