On second thought

A nice, calm, and respectable lady went into the pharmacy, walked up to the pharmacist, looked straight into his eyes, and said, "I would like to buy some cyanide." 

The pharmacist asked, "Why in the world do you need cyanide?"

The lady replied, "I need it to poison my husband."

The pharmacist's eyes got big and he exclaimed, "Lord have mercy! I can't give you cyanide to kill your husband. Absolutely not! You CANNOT have any cyanide!" 

The lady reached into her purse and pulled out a picture of her husband in bed with the pharmacist's wife.

The pharmacist looked at the picture and said, "You didn't tell me you had a prescription.