I can think of three potential explanations for the 'quirky' way in which the artwork is rendered in this sign.
- Instead of in regular cash, the artworker was paid in his/her choice of certain prescription-only over-the-counter "medicines"
- The sign is actually a cunning ninja marketing (2, 3) tool: it's designed to give you the headache which prompts you to go in and buy paracetamol.
- The shop owners nostalgically (and who can blame 'em?) decided to hire the same design team that brightened the lives of our 486s with the fine Day of the Tentacle (screenshot below. Boy, that was a good game.)
Any possibilities I've missed?