Anti-vacuum-lock assemblies for preventing vacuum lock when withdrawing medicinal fluid from a vial comprising a multi-finger bung-type stopper in which the fingers are of sufficient length to protect a collapsing or expanding bladder in the vial from being punctured by the hypodermic needle. In a first embodiment the vial includes one or more side or bottom wall holes to permit ambient air to enter in the space between an internal bladder containing a medicinal fluid and the inner wall of the vial. In another embodiment, an expanding bladder in communication with the exterior expands as fluid is withdrawn from the vial. In a third embodiment a fluted collar is inserted in the vial neck to provide air passages into the space between the medicinal fluid-containing bladder and the interior wall of the vial. The collapse of the medicinal bladder or expansion of the compensation bellows or bladder prevents vacuum lock.
