If you are tempted to buy the jumbo size pain reliever, vitamins, or prescriptions - pay close attention to the expiration date. According to pharmacist Amy Tiemier, those dates really do matter. She says in some cases, medications will become less effective, ineffective, or even unsafe after the expiration date. If you notice any change in how your medicine looks, smells, or works, toss it out. If you're buying in bulk, or ordering prescriptions long term, be sure they'll be used and that you'll be able to store all of them properly. Manufaturers guarantee a medication's effectiveness only before the expiration date, and only if that drug is stored in ideal conditions, usually in a cool, dark, dry spot.