Drug profile

The FDA adverse-event record for Fenbendazole

2,763 FDA reports name Fenbendazole, a high-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#82 of 2,679
by report volume (all drugs)
2,763
adverse-event reports
10.9%
death-coded share
Dog
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Fenbendazole ranks #82 of 2679 by total reports (2,763) and #505 of 1130 by death-coded share (10.9%). National dual: Milbemycin Oxime + Spinosad is #1 of 2679 drugs by total adverse-event reports (149,624) at death-coded-share rank 965 of 1130 drugs with at least 50 reports (2.3%); separately, Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) is #1 highest death-coded share at 97.8% (report rank #821).

149,624
Milbemycin Oxime + Spinosad reports (#1)
97.8%
Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) death share (#1)
#82
This drug, reports of 2679
#505
This drug, death share of 1130

Report volume reflects how common a breed or drug is and how often owners and vets file — not actual risk. Death-coded share ranks are limited to entries with enough reports to be meaningful. The two maps do not agree at #1.

Release-over-release change

What changed in the latest FDA data snapshot

PlainBreed reconstructed the prior snapshot from dated openFDA partitions through 2025 Q4, then compared it with the 2026-07-27 openFDA export. Fenbendazole has 2,763 reports now versus 2,729 in that prior snapshot: 34 more (1.2%).

Report change
+34
Death-coded reports
+3
Death-coded share
−0.0 pts

This compares reported-event counts in two source snapshots. It does not establish a change in real-world risk, product safety, or disease incidence.

Subscribe to Fenbendazole changes

Signature read: death-coded report count at 302 is the most distinctive stamp on Fenbendazole's FDA AER row.

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
2,763
Total Reports
302
Deaths Reported
10.9%
Death-coded share of reports

Active Ingredients

Fenbendazole

Administration Routes

OralUnknownTopicalSubcutaneousOphthalmicRespiratory (Inhalation)OtherIntrauterineAuricular (Otic)Intraocular

Species Affected

Dog 2,258
Unknown 143
Cattle 141
Cat 121
Horse 31
Goat 21
Human 15
Pig 8
Turkey 4
Alpaca 3

Most Affected Breeds

Crossbred Canine/dog 284
Retriever - Labrador 173
Unknown 167
Greyhound 133
Dog (unknown) 108
Pit Bull 101
Chihuahua 97
Retriever - Golden 84
Shepherd Dog - German 84
Domestic Shorthair 82

Most Reported Reactions

Vomiting 665
Diarrhoea 385
Lack of efficacy (endoparasite) - hookworm 300
Anorexia 259
Depression 230
Death 223
Other abnormal test result NOS 146
Lack of efficacy (endoparasite) - tapeworm 136
INEFFECTIVE, HOOKS 132
Lethargy (see also Central nervous system depression in 'Neurological') 130
Lack of efficacy (endoparasite) - roundworm NOS 84
Emesis 83

Outcome Breakdown

Outcome Unknown
715 (40.8%)
Recovered/Normal
373 (21.3%)
Ongoing
350 (20.0%)
Died
261 (14.9%)
Euthanized
45 (2.6%)
Recovered with Sequela
8 (0.5%)

Fenbendazole: high report volume in the FDA AER row

Read these counts as reporting volume, not risk: per our methodology, a widely-prescribed drug will rack up more raw FDA reports in a given year than a rarely-used one at an identical true rate, so we recommend comparing within similar-exposure products rather than across the full 2025 catalog.

High-volume nationwide drug peers

Two openFDA-derived peer sets for Fenbendazole, both floored at ≥50 reports so the neighborhoods stay in the advertised mass.

What to do with this drug

A report does not prove a drug caused the reaction; consult a veterinarian before acting on this data.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

openFDA Animal & Veterinary Adverse Events (FDA CVM) for Fenbendazole (#82 of 2,679 by report volume); death-coded 10.9%. PlainBreed drug row · death-coded report count stamp 302 · vintage 2025.

Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →