FDA Animal Drug Adverse Event Reports: What 1.38 Million Reports Show
The FDA publishes a public database of adverse event reports about animal drugs and other regulated animal products, available through its openFDA animal and veterinary adverse event API. This page reports counts we pulled from that database on October 26, 2026. The data had last been updated by the FDA on October 5, 2026.
Read this first: the FDA states that openFDA data is unvalidated and should not be used to make decisions about medical care. A report records that someone described a problem. It does not prove that a product caused it. These counts are not a safety ranking of any product.
How Many Reports, by Species
| Group | Reports |
|---|---|
| All reports in the database | 1,378,854 |
| Dogs | 1,001,380 |
| Cats | 151,164 |
| All other species, or not specified (calculated by subtraction) | about 226,000 |
Source: FDA openFDA animal and veterinary adverse event endpoint, queried October 26, 2026 (data updated October 5, 2026).
Most Common Reaction Terms
The FDA codes reactions with standardized veterinary terms. The tables below show the five terms that appear most often in reports for each species, as counted by openFDA.
Dogs
| Reaction term (as recorded) | Count |
|---|---|
| Vomiting | 196,274 |
| Diarrhoea | 73,286 |
| Ineffective, heartworm larvae | 68,980 |
| Lethargy | 65,641 |
| Emesis | 63,696 |
Cats
| Reaction term (as recorded) | Count |
|---|---|
| Vomiting | 18,708 |
| Lack of efficacy (ectoparasite), flea | 11,414 |
| Anorexia | 10,927 |
| Lethargy | 9,920 |
| Application site alopecia | 9,247 |
Source: FDA openFDA animal and veterinary adverse event endpoint. “Vomiting” and “Emesis” are separate terms in the FDA’s coding, so we list them as the FDA does rather than combining them.
How to Read These Numbers
- Not every report is about harm. Several of the top terms are “lack of efficacy” or “ineffective” entries, which record that a product did not work as expected, for example against heartworm larvae or fleas.
- Reports are not rates. The database does not say how many animals used a product, so a count cannot be turned into a chance of a problem.
- Dogs account for most reports. More than seven in ten reports are about dogs (1,001,380 of 1,378,854), which says more about who reports and which products are used than about which species is at higher risk.
- Common signs are non-specific. Vomiting, diarrhea and lethargy have many causes, including ordinary illness, so their position at the top of the list is expected in any large set of reports.
If You Think a Product Hurt Your Pet
Contact your veterinarian first. You or your veterinarian can then report the problem to the FDA; see its guide to reporting animal drug and device side effects and product problems. For pet food, see how to report a pet food problem, and for current notices see the recent FDA recall list.
General information, not veterinary advice. Counts are as returned by the FDA’s public API on the date stated and will change as the FDA adds reports.