Where the lot number and expiration date sit on a medicine package

On April 14, 2026, a company began recalling 573 cartons of a prescription ferric subsulfate solution over a single extra digit. The expiration date on each small bottle was printed as 2709114 when it should have read 270914, the code for September 14, 2027, according to FDA's enforcement record for the recall¹. The cartons around the bottles carried the right date. FDA classed it Class III, its lowest-risk tier.

A one-digit slip is a small thing, and it still triggered a nationwide recall. The lot number and the expiration date are the two pieces of print that tie a single bottle back to the batch it came from and forward to any recall notice that might name it. Federal rules set where they appear and what they have to do, and since 2017 the supply chain law has required both inside a barcode as well as in plain type.

What the regulations require

Placement takes one sentence of federal regulation. When an expiration date is required, it "shall appear on the immediate container and also the outer package, if any, unless it is easily legible through such outer package," says 21 CFR 201.17². One exception covers single-dose containers packed in individual cartons, where the date may go on the carton instead.

On the same page, 21 CFR 201.18 explains the point of a lot number in one sentence. The lot number "should be capable of yielding the complete manufacturing history of the package," and "an incorrect lot number may be regarded as causing the article to be misbranded." Misbranding is a violation of federal law, which is why a printing error on a lot code can lead to a recall even when the medicine inside is fine.

Manufacturing rules back this up. FDA's packaging and labeling regulation requires each product to be identified "with a lot or control number that permits determination of the history of the manufacture and control of the batch," under 21 CFR 211.130(c)³. The expiration date has to come from stability testing and be "related to any storage conditions stated on the labeling," according to 21 CFR 211.137⁴. Those conditions are the subject of our guide to storage instructions on medicine labels. Products mixed at the pharmacy, such as antibiotic powders for oral suspension, must carry expiration information for both the dry and the mixed forms. Our explainer on how drug expiration dates are set covers the testing behind the date, and the wider rulebook sits in our guide to CGMP.

Section 211.137 also carries an old carve-out. FDA does not enforce the expiration-date requirement for over-the-counter products whose labeling has no dosage limits and that are stable for at least three years. A handful of store-shelf products can lawfully carry no date at all.

The four codes in the 2D barcode

The Drug Supply Chain Security Act, signed November 27, 2013, as Title II of Public Law 113-54⁵, turned the lot number and expiration date into barcode data. The law defines a "product identifier" with four parts: the National Drug Code, a serial number of up to 20 characters unique to each package, the lot number and the expiration date. On a package, the statute says the data "shall be included in a 2-dimensional data matrix barcode." A shipping case of identical packages can use a linear or a 2D barcode.

Manufacturers had to start printing product identifiers on packages by November 27, 2017, and repackagers by November 27, 2018, according to FDA's 2021 question-and-answer guidance on product identifiers⁶. The same guidance sets out how the human-readable version should look, so that a pharmacist or nurse can check a date or copy a lot number into a patient record without a scanner. Our explainer on the DSCSA and drug serialization covers the tracing system the codes feed.

Source: FDA, Product Identifiers Under the Drug Supply Chain Security Act, Questions and Answers (June 2021).

Two details in that guidance answer common questions. When space forces a year-and-month date, FDA reads it as the last day of that month, so a date printed 2021-07 "would be interpreted by FDA to mean that the drug expires on July 31, 2021." And a QR code does not count. FDA says a QR code "is not the same as a 2D data matrix barcode and does not encode the same type of information." The older linear barcode that FDA required on hospital-use drugs in 2004 is a separate thing; it must carry the NDC at minimum. Our piece on the NDC number breaks down its segments.

What reaches the patient

A prescription that a pharmacist counts into a vial travels under a different label. Federal law exempts a dispensed prescription from most package labeling rules if its label carries "the name and address of the dispenser, the serial number and date of the prescription or of its filling, the name of the prescriber," the patient's name if stated, and the directions and cautions, under section 503(b)(2) of the Food, Drug, and Cosmetic Act⁷. The "serial number" in that list means the prescription number, a different code from the package serial in the barcode, and the manufacturer's lot number does not appear on the federal list. Our guide on how to read a prescription label walks through each line, and the pharmacy that filled a prescription is the place to ask which lot it came from.

Why recalls run on lot numbers

Recalls are organized around lots because the manufacturing rules require it. Every manufacturer must keep "a system by which the distribution of each lot of drug product can be readily determined to facilitate its recall if necessary," says 21 CFR 211.150(b)⁸. When a recall starts, FDA's recall rule says the notice to customers should "identify clearly the product, size, lot number(s), code(s) or serial number(s)," under 21 CFR 7.49⁹.

FDA's public recall data carry the same codes. Each record in the agency's openFDA enforcement dataset¹ has a field listing the affected lots and dates. In the ferric subsulfate case it reads "Lot #: 640911253, Exp Date. 09/14/2027."

Serial numbers now let a recall go narrower than a whole lot. In January 2026, a maker of a pegfilgrastim biosimilar began a Class I recall of 116 cartons from one lot that had been stored at controlled room temperature instead of in a refrigerator. The FDA record¹ lists each affected carton by its 12-character serial number, leaving the rest of the lot out of the recall. Our guides on checking whether a medicine was recalled and reading an FDA recall notice show where to match these codes against a package.

When the codes themselves are wrong

GxRadar counted recall records in the openFDA enforcement data from 2012 through October 28, 2026. Of 18,076 drug records, 182 give the reason "Incorrect or Missing Lot and/or Exp Date." None was Class I; 90 were Class II and 92 were Class III. A separate group of 183 records says the manufacturer's stability data did not support the expiration date printed on the label, a problem with the testing behind the date. Most of those came in 2015 and 2016.

Source: GxRadar analysis of openFDA drug enforcement records, 2012 to October 28, 2026, matched on the reason-for-recall text. Each record is one product line, so a single event can produce several records. No records matched in 2012.

Most of these errors are mundane. In July 2025, a manufacturer recalled 7,668 bottles of amlodipine and benazepril capsules because they were "released with wrong expiry date as Feb.2027 instead of Jan.2027," according to FDA's record in the openFDA enforcement data¹. FDA classed it Class II, a step above the ferric subsulfate case. Our recall tracker shows all reasons by year, and the amlodipine page has that drug's recall history.

At the smallest pharmacies, the barcode system that carries these codes is still being phased in. On August 6, 2026, FDA extended its exemption for small business dispensers from the electronic, package-level tracing requirements until November 27, 2027, according to the agency's exemption notice¹⁰.