The invention relates to a closure cap for a container filled with medicinal fluid, which container has an aperture piece which is sealed off by a diaphragm which can be punctured. The closure cap has a cap-shaped closure body (1) and a drinking neck (4) with a drinking opening (4a) which is pivotable between a first position, in which the drinking neck bears against the closure cap, and a second position, in which the drinking neck projects from the closure cap. In addition, the closure cap has means (20, 22) for puncturing the diaphragm which seals off the aperture piece of the container, which means (20, 22) interact with the drinking neck in such a way that, as the drinking neck (4) is pivoted, the diaphragm is punctured such that a connection is produced between the opening (4a) of the drinking neck and the container interior. The closure cap is characterized in that the closure body has, in addition to the opening (4a) of the drinking neck (4), an opening (20a, 24) for ventilating the container during drinking.