A tamper resistant cap for a container includes an inner cap and an outer cap. The inner cap has a threaded inner surface, and an upper surface with a plurality of upwardly extending teeth. The outer cap houses the inner cap and defines a central bore thereabove with an inner engagement surface. On an intermediate layer of the outer cap, below the upper bore, there are a plurality of downwardly extending teeth. The tamper resistant cap is releasably securable onto a neck of the container by engagement with the threaded inner surface and removable therefrom by applying a downward force to the outer cap to mesh the upwardly and downwardly extending teeth. The central bore is engageable with a frangible post of the container to effect removal thereof.