Abstract: An infinitely stacking receptacle cap cooperates with existing bottles and bottle caps for holding pills and other articles separate from liquid within the bottle. In one embodiment, the bottle has a liquid impervious body and a neck with external threads. The infinitely stacking receptacle cap has a divider wall, and an internally threaded cavity adjacent to and extending from the divider wall in a first direction encompassing and engaging with the bottle neck threads. The internally threaded cavity has a height corresponding to the bottle neck height. An externally threaded infinitely stacking receptacle cap neck is adjacent to and extends from the divider wall in a direction generally opposed to the internally threaded cavity. The height of the externally threaded stacking receptacle cap neck is equal to the bottle neck height.