Methodology

Every figure on this site is a count of adverse event reports in the openFDA Animal & Veterinary bulk files, release of 28 Sep 2026. Nothing is modelled or estimated. This page explains how a report becomes a count.

What one report is

A report is one submission to FDA's Center for Veterinary Medicine about one animal or group of animals: the drugs the animal was given, the signs observed (coded with the VeDDRA dictionary), the animal's species, breed, age and weight, the outcome at the time of reporting, and whether the reporter classed the event as serious. Reports are also filed when a product did not work as expected and when packaging or tablets were defective with no animal involved. About 35% of all reports are of those kinds.

Brands are masked, so drugs are counted by active ingredient

openFDA masks the brand name and manufacturer fields of every record (they read "MSK"). This site does not reverse that. It does not read the application number that records carry, and no figure is attributed to a brand, trade name, application or company. What each drug entry does disclose is its active ingredients, and that is the key for every statistic.

A drug page covers one set of active ingredients as recorded for a drug entry: a single ingredient, or a combination of up to six. A pooled ingredient page counts one ingredient alone and in every combination; it is built only where no single set holds 90% or more of the ingredient's reports, so that two pages never show nearly the same numbers (248 ingredients are covered by their drug page alone).

How ingredients are recognised

The ingredient field is unmasked but untidy: it can hold a plain name, a list, or a description with a strength and form. Each entry is scanned for the names of active ingredients in FDA's Green Book (2,429 approved applications) and for a short fixed list of generic substances that veterinarians commonly prescribe from human labels (gabapentin, prednisone, trazodone and similar). A few common short forms are mapped to the Green Book name. Everything else in the field, including brand names, vaccines and descriptions typed by reporters, is ignored, and a drug entry with no recognised ingredient is not counted under any drug. Salts and forms are kept as FDA lists them. Because the field is filled in by the submitter, it can be incomplete: a three-ingredient product is sometimes recorded with two, and then sits under that two-ingredient set.

Green Book reference lists

Each drug and ingredient page ends with a separate section listing the FDA-approved products that contain the ingredient or combination: trade names, sponsor, active ingredients, the major species the Green Book search lists, and the application number. This is reference information from the Green Book only. It carries no counts, and nothing on the site says which product a report concerned. Approval dates are not part of the Green Book listing files and are not shown. Trade names are also search aliases that lead to the ingredient's page.

Counting rules

• A report that lists three drugs counts once for each distinct ingredient set, and once for each distinct ingredient. Listing means the animal received the drug; FDA's files do not say which drug, if any, the reporter suspected.
• A report that lists five signs counts once for each sign, so shares of signs add to more than 100%.
• "Classed serious" is the report's own seriousness flag, as a share of reports that state it either way.
• "Death or euthanasia recorded" means the report lists "Died" or "Euthanized" among its outcomes. A report about several animals can carry several outcomes.
• Months are months in which FDA first received the report. 92 records with no usable receive date are left out.
• Spelling variants of one VeDDRA term (with and without a cross-reference note) are pooled. Legacy FDA terms written in capitals in older reports are shown in sentence case and marked as legacy terms.
• Breed pages use reports that give a single breed. Crossbred animals and placeholder labels ("unknown", "other") count in species totals only. Breed names are FDA's labels put into everyday order.
• Age bands convert days, weeks and months to years. Weight is in kilograms as reported.

Thresholds

A page is built and indexed only when there is enough to say: drug pages (ingredient sets) with 50 or more reports (those with 20 to 49 exist for links but are marked noindex and left out of the sitemap), ingredients 50, species 100, breeds 100, reported signs 200, months 300.

Comparisons, shares and what they mean

Each page sets its entity beside a wider pool: an ingredient set beside all reports naming its most specific ingredient and all reports for its main species; a breed beside its species; an ingredient, sign or species beside the whole database. Normalisation is by shares: share of all reports, share of the species' reports, share of the pooled ingredient's reports, and average reports per year over the period in which the entity appears. These are shares of reports. They are not rates of occurrence, because the number of animals treated or doses sold is not public, and no population estimates are used.

FDA states that these data cannot be used to estimate the risk associated with a product or to compare one product with another. Drugs differ in how many animals receive them, which animals (age, health, species), how long they have been sold, how much publicity they have had, and how diligently reports are collected. Tables that list several ingredients are ordered by report count for navigation and carry that statement.

Trends

The trend on each page compares the latest 12 months of receipt with the 12 months before. FDA posts reports quarterly with a delay of three to six months, so the newest months are incomplete and usually grow in later releases; a small decline in the latest period is therefore expected. FDA attributes much of the long-run rise in reports to improved reporting.

Plain-language glosses

VeDDRA terms are shown exactly as coded, with a short gloss in brackets from a fixed dictionary maintained by this site ("Emesis [vomiting]"). The gloss explains the word and adds nothing to the report. Terms without an entry are shown without one.

Text on the pages

Summaries and answers are assembled from fixed sentence templates filled with the counts. Nothing is written by a language model, and no sentence attributes an event to a product.

Build

The site is rebuilt daily. Each year of openFDA files is reduced to a table of counts; a year is reprocessed only when FDA's file listing shows a change in it. The Green Book copy is refreshed weekly.