Cough cure..
 

A pharmacist walks into his shop to find a customer leaning against the wall.

"What's wrong with him?", he asks his assistant.
"Oh, he came in to get something for his cough", the assistant replies.
"I couldn't find the cough syrup, so I gave him a bottle of liquid laxative."

"What!, You can't treat a cough with laxatives!", splutteres the pharmacist.

"Yes, you can.", says the assistant. "Now he's too afraid to cough!"