What the storage instructions on a medicine label mean

In June 2026, a company began recalling 74 vials of gemcitabine, a cancer drug given by infusion, for a reason that had nothing to do with how the drug was made. The vials "were stored incorrectly in a controlled room temperature environment instead of a refrigerated environment," according to FDA's enforcement record¹. FDA classed the recall Class II.

At the end of August, another recall began after 296 cartons of a hormone implant "sat in a non-temperature-controlled" delivery trailer "at ambient outdoor conditions for 25.5 hours," FDA's record shows¹. In both cases the only thing wrong was the temperature the product had been kept at, measured against a single line of label text.

That line, the storage statement, is one of the more consequential sentences on a medicine label, and its vocabulary is defined precisely. This explainer covers what federal rules require of storage statements, what terms such as "controlled room temperature" mean in degrees, how short excursions are judged, a revision to the room-temperature definition proposed in 2026, and what FDA's recall records show about storage failures.

Why the storage line is tied to the expiration date

Under federal manufacturing rules, a medicine's expiration date and its storage instructions come from the same stability studies. "Expiration dates shall be related to any storage conditions stated on the labeling, as determined by stability studies," says 21 CFR 211.137(b)². A date printed on a carton holds only for a product kept the way the label says.

The international stability guideline that FDA publishes as guidance, ICH Q1A(R2), makes the same link. "There should be a direct link between the label storage statement and the demonstrated stability of the drug product," the guideline says³. It also asks for specific instructions "particularly for drug products that cannot tolerate freezing," and says vague terms "such as ambient conditions or room temperature should be avoided."

For prescription drugs, the storage statement has a fixed home in the full prescribing information. Section 16, "How Supplied/Storage and Handling," must include "special handling and storage conditions," under 21 CFR 201.57(c)(17)⁴. Section 16 of any label can be read on DailyMed; our guide on looking up a drug on DailyMed shows where. Patient leaflets often repeat the instruction in plainer words, as our piece on Medication Guides and patient package inserts describes.

Rules also follow the product down the supply chain. Manufacturers must store drugs "under appropriate conditions of temperature, humidity, and light so that the identity, strength, quality, and purity of the drug products are not affected," says 21 CFR 211.142⁵. Wholesale distributors must store prescription drugs according to the labeling or the official compendium, the United States Pharmacopeia (USP), and keep temperature and humidity records, under 21 CFR 205.50(c)⁶. If a label sets no storage requirement, that rule says the drug "may be held at 'controlled' room temperature, as defined in an official compendium." Our explainers on what drug wholesalers do and how a pill gets from the factory to the pharmacy trace that chain.

What the label words mean in degrees

USP's general chapter on packaging and storage, numbered 659, is where the words on a label get their numbers. A 2016 review in the Saudi Pharmaceutical Journal tabulated the USP definitions⁷ used on labels.

Source: USP general chapter 659 definitions as reported by Kumar and Jha, Saudi Pharmaceutical Journal (2016). Fahrenheit figures converted by GxRadar and rounded.

A label reading "Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F)" is quoting the controlled room temperature definition almost word for word. "Refrigerate" means the 2°C to 8°C band, and many refrigerated products also carry a separate "do not freeze" line, the kind of specific instruction ICH Q1A(R2) asks for.

Insulin shows how a single label can carry more than one storage condition. FDA says the labels of all three US insulin manufacturers recommend refrigerator storage "at approximately 36°F to 46°F," and that vials or cartridges "may be left unrefrigerated at a temperature between 59°F and 86°F for up to 28 days and continue to work," according to FDA's page on insulin storage in emergencies⁸. The 59°F to 86°F range is the same 15°C to 30°C band USP allows for excursions.

How excursions are judged, and a 2026 proposal

No warehouse or delivery truck holds a perfectly steady temperature, so USP pairs its room-temperature range with a calculated figure called mean kinetic temperature, or MKT. In a proposal published in 2026, USP's packaging and distribution expert committee described MKT as "the primary tool for evaluating short-term temperature excursions beyond 25°," and said MKT should be calculated over the product's time in the holder's possession "or 30 days when the exact duration is unknown," according to USP's briefing on the revision to chapter 659⁹. The same briefing cites a companion chapter "noting that the maximum allowable excursion duration is 24 hours."

The proposal would also change the definition itself. "Currently, USP defines CRT as 20°–25°, with excursions permitted from 15° and 30°," the briefing says. The Japanese and European pharmacopoeias and the World Health Organization use 15°C to 25°C, and USP's committee proposed adopting that lower bound for global consistency and to cut heating demand in warehouses, citing "estimated energy savings of 10%–15%." Upward excursions would still be judged by MKT.

Until USP finalizes a revision, labels and wholesaler rules keep pointing to the 20°C to 25°C definition. The federal wholesale rule refers to "the current edition of an official compendium," so its reference point is whatever USP's chapter says at the time.

What FDA's recall records show

GxRadar searched the reason-for-recall text of 18,076 drug recall records in FDA's openFDA enforcement data¹, 2012 through Oct. 28, 2026, for any mention of temperature. There were 586 such records, 16 of them Class I. Most came in a few bursts, each a single storage or shipping event that put hundreds of product lines on FDA's weekly enforcement report at once.

Source: GxRadar analysis of openFDA drug enforcement records through Oct. 28, 2026. Each record is one product line.

Four posting dates account for 470 of the 586 records. The other 116 are spread across 15 years, and recent ones read much like the 2026 gemcitabine and implant cases: refrigerated products kept at room temperature, or shipments delayed in transit. Our recall tracker groups all recall reasons by year, and our guide on checking whether a medicine was recalled explains how to match a lot number against a notice.

The label at home

None of these definitions change once a medicine leaves the pharmacy, though nobody logs the temperature of a kitchen. FDA's consumer guidance tells readers to "read the label to see if there are specific storage instructions for your medicine," warns that improper storage, such as a damp bathroom cabinet, "can contribute to decreased effectiveness in medicines that have not reached their posted expiration date," and suggests a cool, dry place such as a dresser drawer or closet shelf, on its page about expired medicines¹⁰.

Whether a particular product is still usable after a hot car or a freezer mishap is a question the label alone may not answer, and it is one to put to a pharmacist. The date and lot printed next to the storage line are covered in our explainer on how drug expiration dates are set. Medicines that can no longer be used have their own rules, set out in our guide on disposing of unused medicines.

USP's revised room-temperature definition, if adopted, would lower the bottom of the controlled range from 20°C to 15°C (59°F) while leaving the 25°C ceiling in place.