The expiration dates on your over the counter meds are there for a reason. But sometimes it pays to bend the rules. Does A Drug’s Expiration Date Matter? Check out our list. Take This, Toss That.

Imagine finding months-old milk buried in the back of your fridge. If you dare open it, you definitely won’t risk drinking it – the foul smell and floating chunks are big hints that what you’re holding is unfit for cereal. Upchuck averted. But what if we replaced the milk with milk of magnesia?
Hmmm. It looks okay. And it doesn’t smell funny… Ultimately, you’ll decide whether to use or lose the laxative based on the only clue you have: the expiration date. And that’s fine – assuming you don’t have a coin to flip. The truth is, many OTC meds don’t morph into poisons or placebos one minute – or one year – past their expiration date. Those dates simply signify how long the drugmaker can guarantee potency and safety, says David Apgar, an assistant professor of pharmacy practice and science at the University of Arizona. “If they tested it for three years, that doesn’t mean it won’t last for six. It just hasn’t been proven.”
So how do you know when expiration dates matter? Turn the page for your chuck-it cheat sheet. We’ll show you which numbers to heed, stretch or ignore.

Rule of thumb: before you use any expired medication, consider the worst thing that could happen if the drug doesn’t work. If it’s sunscreen, you could be courting skin cancer. So always discard expired tubes and bottles, says Dr Stephen Hoag, a professor of pharmaceutical sciences at the University of Maryland. In fact, if you allow your sunblock to bake on the beach with you instead of leaving it indoors or in the shade, consider tossing the bottle before the expiration date. Intense heat can accelerate the breakdown of the active ingredients, potentially leaving you unprotected.

“It’s well documented that aspirin loses potency over time,” says Dr Lee Cantrell, a professor of clinical pharmacy at UC San Francisco. For example, in a recent study published in JAMA Internal Medicine, Cantrell and his colleagues discovered that decades-old aspirin retained only about 1% of its original strength. But what about a bottle that’s just one year past its expiration date? In a case like this, don’t rely on your eyes – your nose knows the answer.
“Aspirin breaks down to acetic acid, which smells like vinegar,” Apgar says. “That’s not dangerous, but the drug would not be effective.”

Benzoyl Peroxide (acne treatment)
In the fight against time, benzoyl peroxide has a significant size advantage. “It’s a fairly small molecule,” says Dr Mikael Langner, a dermatology researcher at UC San Francisco. Smaller molecules absorb into your skin easily, and there’s a high concentration of benzoyl peroxide in each dab of cream. So losing a few molecules won’t seriously alter the zit-zapping action.

Although some mouthwashes contain an antiseptic, they also have a high percentage of water. That means there’s a chance of bacterial growth – especially after two years, when the potency of the active ingredient starts to diminish, says Dr Jennifer Jablow, a dentist. Of course, if you’re still working on the same bottle after two years, your love life has probably expired too.

Dextromethorphan (cough suppressant)
Cough up the money for a new bottle. In a study from Spain, researchers subjected cough syrup to stability testing and found that dextromethorphan degraded more than the other syrup ingredients did. Plus, as with many liquids, time isn’t kind to cough syrup: the alcohol can evaporate or the active ingredient can sink to the bottom, leaving an unequal distribution of what’s left, says Apgar.

Hydrocortisone Cream
That itch is a bitch, and you don’t want an infection too. “Anywhere you have high moisture content,
as with creams, you have a greater opportunity for bacteria to grow,” says Dr Kelly Reynolds, a professor of public health at the University of Arizona. And when you touch the tube’s tip, you contaminate the cream. “Eventually the preservatives wear off, so bacteria can proliferate,” she says.

Guaifenesin (expectorant)
Good news for hackers: sealed guaifenesin tablets stay potent for an average of about seven years after their use-by date, reports a study from the FDA. “It’s a relatively stable chemical,” says Apgar. However, when guaifenesin is in liquid form (which it generally is), live by the label. The drug could crystallise at the bottom of the bottle, and “the top teaspoons of liquid wouldn’t have much active ingredient,” he warns.

Sometimes. “We found that some brands could last for years past the expiration,” says Dr Wendy
Cory, an assistant professor of analytical chemistry at the College of Charleston. But read the rest of the label: if polyethylene glycol, polysorbate 80 or povidone are listed as ingredients, buy a new bottle. These chemicals speed ibuprofen’s breakdown, Cory’s study shows.

Maybe you ran out of your regular toothpaste and now find yourself staring at a long-forgotten tube that’s been lurking in the back of your medicine cabinet since 2009. Let it stay forgotten. “After two years, fluoride can lose its strength, so it won’t bind as well to your teeth,” says Jablow.
“The toothpaste won’t be dangerous to use, but you’ll miss out on protection against cavities or plaque.” What’s more, she says, the mint flavouring may start to disintegrate, leaving you with less-than-fresh breath.

Expiration decade would be more like it: in a study by Cantrell, unopened acetaminophen that was 28 to 40 years out of date still retained 99.7% of the original dosage, though an opened bottle won’t be as hardy. Also, Cantrell warns that his study tested potency and not efficacy or safety. So if that ancient box of tablets doesn’t seem to be working, don’t pop another, because you have no idea how much of the drug remains (and how large of a dose you’re taking). Just buy a new bottle.

Terbinafine (athlete’s-foot cream)
That dusty tube of antifungal cream won’t transform into something funky. It breaks down into harmless substances, says Langner. “That means it’s okay to use – you just may not be getting the full efficacy.” Give your cream a quick once-over before you go slathering it between your toes: “Do you notice some difference in texture – is it thinner? Has it developed an acrid odour? Is it hard?” says Langner. If the answer to any of these questions is yes, spring for a new tube. You’ll do your feet (and the other guys in the changing room) a big favour.

Salicylic Acid (wart remover)
Even after the expiration date has faded from the box, these products may still be able to erase warts. “I have acids that have been sitting in my lab for years. The pH doesn’t change,” says Langner. “If the pH is still what it was when you purchased the drug, it will still be effective.” Plus, with acids, “there is less possibility of degradation upon exposure to the elements, like light, water and heat,” he adds. The best test? Give the stuff a try. “You can use your body’s response as a gauge for whether or not the product is working,” says Langner.

Loratadine (antihistamine)
This, can probably survive just about anything you throw at it. In a study from India, scientists subjected loratadine tablets to rigorous stress tests – in one experiment, the pills were in 70°C heat for six hours, and in another, they were exposed to direct sunlight for 24 hours. In both cases, more than 99% of the active ingredient survived. That’s nothing to sneeze at. “I suspect it would be okay after expiration,” says Hoag. And as it breaks down, Apgar adds, “it’s not going to turn into a dangerous chemical.”

This active ingredient soldiers on, according to a joint study from the FDA. The scientists discovered that naproxen retains its painkilling potency for an average of 52 months after the expiration date. Keep in mind, however, that the tablets tested were still sealed in their original packaging, so an opened bottle probably won’t last quite as long. And if you notice that your pills have changed colour or started to crumble, just discard them, says Cory.

Eye Drops
Drop expired drops in the trash; otherwise you’re putting your eyes at risk. “These products can become contaminated with bacteria – if, for example, you touch the dropper to your eye,” says Apgar.
“If they’re kept at room temperature, the bacteria can grow quickly.” (That’s why you should store your drops in the fridge: germs can’t proliferate as fast in cool conditions.) And always toss clear drops that have turned cloudy – even if the expiration date is far off. Murkiness signals contamination.

Isopropyl Alcohol
Don’t be afraid to hit the bottle after the date. “Isopropyl alcohol is a very simple chemical,” says Hoag. “There’s just not much that could happen to it.” And even though it’s liquid – a drug form that typically favors bacterial growth – as much as 99% of that liquid is alcohol, a chemical known for its antimicrobial activity. “The higher the alcohol concentration, the more likely it is to remain stable for a long time,” Apgar says. As long as the liquid is clear and not cloudy, you’re in the clear to use it.

You won’t get the most out of your meds if you expose them to heat, humidity or light – all three make drugs degrade faster. That means the bathroom, kitchen and your car are off-limits. You might assume that the cool, dark refrigerator is ideal. Wrong. It’s too humid, says David Apgar, an assistant professor at the University of Arizona. The exceptions: eye drops and products specifically labelled for refrigeration. The best place for your other meds? The bedroom, away from windows and lamps.