Abstract: A tamperproof container and cap assembly in which the container carries a circumferential radially extending flange which cooperates with the skirt of the cap to prevent the cap from being removed until a portion of the cap skirt is removed. The cap skirt comprises an upper portion and a lower portion, with the lower portion forming a tear-off strip that is connected to the upper portion by means of vertically oriented stacking ribs. The ribs are dimensioned so as to allow a plurality of caps to be stacked upon one another. The lower portion of the skirt defines an opening which enables an operator to insert a tool therein and then to tear the lower portion away from the upper portion.