Abstract: A "childproof" container closure comprises a threaded neck member and a threaded closure cap or plug member cooperating therewith. One member bears a raised helical thread having a stop end and the other member defines two helical paths in which the helical thread may be engaged, one of which paths allows the cap or plug member to be removed from the neck member and the other having at its end a blocking member adapted to engage the stop end of the helical thread. The cap or plug can be resiliently sprung axially to move the raised helical thread from one helical path to the other.