A chemist walks into the store he owns... and he sees a woman, leaning up against a wall near the counter.

"What's wrong with her?" he asks his assistant.

"She was sneezing and needed allergy medicine, " explains the assistant, "but I couldn't find any, so I sold her a bottle of laxatives instead."

"WHAT?" bellows the chemist. "You can't treat allergies with laxatives!!!"

"Of course you can," replies the assistant, pointing at the woman. "Look at her, she's too scared to sneeze now!"