Medicine expiration dates appear in several formats, but they all tell you the same thing: the last date the manufacturer guarantees full potency and safety. You’ll typically find them printed on the outer box, the bottle label, or stamped directly onto blister packs. The tricky part isn’t finding them; it’s interpreting the different formats and understanding what they actually mean for your safety.
Common Expiration Date Formats
Most prescription and over-the-counter medications use one of these formats:
- MM/YYYY (e.g., 06/2026): The most common format. This means the medication is good through the last day of that month, so 06/2026 means June 30, 2026.
- MM/DD/YYYY (e.g., 06/15/2026): A specific calendar date. The drug expires on that exact day.
- YYYY-MM-DD (e.g., 2026-06-15): An international format you’ll sometimes see on imported or generic products. Read it as year first, then month, then day.
- Month and year spelled out (e.g., JUN 2026 or June 2026): Same as MM/YYYY, good through the end of that month.
Look for the abbreviation “EXP” before the date. Some products use “Use by,” “Use before,” or “Best by” instead. If only a month and year are listed with no specific day, always assume the expiration is the last day of that month.
Where to Find the Date on Your Packaging
FDA regulations require the expiration date to appear on the immediate container (the bottle or blister pack that directly holds the pills) and on the outer package. There’s one exception: when single-dose containers come in individual cartons, the date can appear on the carton alone rather than on each tiny container inside.
On prescription bottles from a pharmacy, the expiration or “discard by” date is usually printed on the pharmacy label itself. This date may differ from the manufacturer’s original expiration because the pharmacist calculates it based on when the medication was dispensed and repackaged. The pharmacy-assigned date is generally shorter and is the one you should follow.
On over-the-counter products, check the bottom of the box, the crimped end of a tube, or the back of a blister card. Bottles often have the date stamped on the cap, the bottom, or printed on the label near the lot number.
Lot Numbers Are Not Expiration Dates
A common source of confusion is the lot number (sometimes labeled “LOT” or “Batch”), which often sits right next to the expiration date. Lot numbers are used for manufacturing tracking and product recalls, not for telling you when the drug expires. They can contain digits that look like dates, such as “23145,” which in some systems represents the 145th day of 2023. But this encodes the manufacturing date for the company’s internal use, not an expiration date for you.
If you see two strings of numbers near each other on a label, the one preceded by “EXP” is your expiration date. The other is the lot number. When in doubt, call the pharmacy or check the manufacturer’s website.
The Open Jar Symbol on Topicals
Creams, ointments, and eye drops sometimes carry a small icon that looks like an open jar with a number inside, such as “6M” or “12M.” This is the period-after-opening symbol, and it tells you how many months the product remains good after you first open it. A label reading “12M” means you have 12 months from the day you break the seal, regardless of the printed expiration date. Whichever date comes first, the expiration date or the end of the period-after-opening window, is the one that applies.
This matters especially for eye drops and liquid antibiotics, where bacterial contamination becomes a real concern once the container is opened. Writing the date you opened the product on the label with a marker is a simple habit that takes the guesswork out.
What the Expiration Date Actually Guarantees
The printed date is the manufacturer’s guarantee that the drug retains at least 90% of its labeled potency when stored under recommended conditions. After that date, there’s no guarantee of safety or effectiveness. A joint program between the FDA and the Department of Defense tested 122 different drug products across over 3,000 lots and found that 88% retained their potency for at least one year beyond the original expiration date, with an average extension of 66 months. But the results varied enormously from drug to drug, so this isn’t a green light to raid the back of your medicine cabinet.
The form of the medication matters. Solid tablets and capsules tend to be more stable over time than liquids, suspensions, and reconstituted antibiotics. Liquid formulations are more susceptible to bacterial growth and chemical breakdown. Sustained-release tablets and capsules present a particular risk after expiration because degradation can alter how much of the active ingredient releases at a given time, potentially delivering too much or too little.
Storage Affects the Real Expiration Date
That printed date assumes you’ve stored the medication properly, which for most drugs means a cool, dry place away from direct light. The bathroom medicine cabinet, despite its name, is one of the worst places to keep medication. The humidity from showers can cause tablets to break down, and heat accelerates chemical degradation. Blood glucose test strips stored in humid environments can give inaccurate readings. A kitchen cabinet away from the stove, sink, and hot appliances is a much better choice.
If your medication has been exposed to extreme heat (left in a hot car, for instance) or moisture, it may have degraded well before the printed expiration date. Tablets that have changed color, smell unusual, or crumble easily are showing visible signs of breakdown. Liquids that appear cloudy, have particles floating in them, or have changed color should not be used regardless of the date on the label.
How to Dispose of Expired Medications
The safest disposal method is a drug take-back program. Many pharmacies and police departments host collection events or have permanent drop-off bins. Pre-paid mail-back envelopes are another option in some areas.
A small number of medications, primarily opioid painkillers and a few other high-risk drugs, are on the FDA’s “flush list.” These should be flushed down the toilet if no take-back option is available, because the risk of accidental poisoning or misuse outweighs the environmental concern. The flush list includes medications containing fentanyl, oxycodone, hydrocodone, morphine, methadone, and several others. For everything not on the flush list, the recommended home disposal method is mixing the medication with something undesirable like coffee grounds or dirt, sealing it in a container, and placing it in the household trash.