Cough medicine.
A pharmacist is about to take a lunch break and he says to his assistant, “I’ll be back in an hour, keep an eye on things”.
Upon his return, he notices a man outside the pharmacy, standing against the wall, clutching his abdomen, obviously in some pretty serious discomfort.
He continues into the store and asks his assistant, “what’s with the guy outside?” to which the assistant says “he came in with a bad cold. I couldn’t find the cough medicine, so I gave him some laxatives.”
“Laxatives??!!” exclaims the pharmacist, “that’s not gonna do anything for his cold!”
“Sure it will,” replies the assistant “Look, he’s afraid to cough!”