A small and simple built-in shelf, from Better Homes and Gardens. You could even fit a shelf like this in between the studs in the wall, making it a pretty easy DIY project. It could work in my powder room.
Restore Order Limit medicine cabinets to items you use every day. Keep medications in original containers on a high shelf or other safe spot, particularly if there are small children in the house. Store remaining items one layer deep, doubling space with