The owner of a drug store walks in to find a guy leaning heavily against a wall...

[4wheelin]

The owner asks the clerk, "What's with that guy over there by the wall?" The clerk says, "Well, he came in here this morning to get something for his cough. I couldn't find the cough syrup, so I gave him an entire bottle of laxative."

"You idiot! You can't treat a cough with laxatives!"
"Oh yeah? Look at him, he's afraid to cough!"