This invention proposes a cap (2) for a container (1) which has an upper surface (10), wherein the cap (2) includes a body configured to attach to the upper surface of the container, and a perforation platform (3) comprising a plurality of protruding perforating elements (4a, 4b), so that the perforation platform (3) is displaced vertically with respect to the body from a resting position to a working position, and wherein the perforating elements (4a, 4b) perforate an upper lid of the container. In the resting position, the perforation platform (3) is horizontally aligned with the upper surface (2a) of the body of the cap (2), while, in the working position, the perforation platform is displaced vertically, and in its entirety, a distance so that the protruding perforating elements (4a,4b) exclusively penetrate the upper surface (10) of the container (1) and the perforation platform (3) remaining in a parallel position to the upper surface (2a) of the cap (2).