Drug profile

The FDA adverse-event record for Zeranol

131 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Zeranol. See the species affected, top reactions, and outcomes below.

131
adverse-event reports
13.7%
death-coded share
Unknown
most-reported species
61
Implant, Abnormal - top reaction
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Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
131
Total Reports
18
Deaths Reported
13.7%
Death Rate

Active Ingredients

Zeranol

Administration Routes

UnknownSubcutaneousIntralesionalIntramuscular

Species Affected

Unknown 96
Cattle 30
Human 3
Sheep 1
Horse 1

Most Affected Breeds

Unknown 99
Crossbred Bovine/Cattle 9
Cattle (unknown) 7
Mixed (Cattle) 4
Aberdeen Angus 3
Cattle (other) 3
Holstein-Friesian also known as Holstein 2
Brangus 1
Cattle (unspecified) 1
Crossbred Ovine/sheep 1

Most Reported Reactions

Implant, Abnormal 61
Containers, Abnormal 32
Dispenser, Abnormal 21
Death 16
Anaphylaxis 4
Accidental exposure 4
Underfilling, Package 4
Respiratory tract disorder NOS 4
Dyspnoea 3
Unclassifiable adverse event 3
Injection site pain 3
Collapse (see also 'Cardio-vascular' and 'Systemic disorders') 2

Outcome Breakdown

Died
18 (75.0%)
Outcome Unknown
5 (20.8%)
Recovered/Normal
1 (4.2%)

Zeranol Adverse Event Insights

131 reports name Zeranol; 18 recorded a death outcome (13.7% of reported events, not a population-level mortality rate). Active ingredient: Zeranol. Administration routes: Unknown, Subcutaneous, Intralesional, Intramuscular.

By species: Unknown (96 reports), Cattle (30 reports), Human (3 reports). By breed: Unknown (99), Crossbred Bovine/Cattle (9), Cattle (unknown) (7).

Leading clinical signs: Implant, Abnormal (61), Containers, Abnormal (32), Dispenser, Abnormal (21), Death (16). Outcome, 24 coded reports: Died leads at 75.0%.

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.

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

Every figure on PlainBreed is rendered directly from FDA openFDA adverse event data, no number is typed in by an editor. This page draws directly on FDA openFDA data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.