Health and safety rules are often written in blood

Or they should be sold in a set with rubber sheets.

Pretty sure that mixing laxatives with anything would result in a bad time. Alcohol, cocaine, viagra...

Take this sign and put it on the shelves in any sort of store. Makes people doubt themselves and boycott the product out of fear.

Pharmacist here to spoil the joke: this isn't even a common contraindication among these groups. In fact stimulant laxatives take 6-8 hrs to work so are taken at night on purpose. Always reminds me of my old pharmacy manager saying "Take 1 in the PM for a BM in the AM".