Pet Safety / Compounds / Zearalenone

Is Zearalenone safe for dogs and cats?

Moderate risk for pets

Dogs exposed to ZEN-contaminated grain-based pet food may develop hyperestrogenism: vulvar swelling and discharge in females, mammary gland development in males, and reproductive cycle disruption. Pet food recalls have included ZEN among the triggering mycotoxins. Dogs may eat moldy corn or corn-based food waste, creating acute exposure risk. The estrogenic effects in dogs can mimic ovarian cysts or pyometra, potentially leading to unnecessary veterinary procedures if ZEN exposure is not considered in the differential diagnosis. Clinical signs typically resolve after removing the contaminated food source.

What is zearalenone?

The IUPAC name is (4S,12E)-16,18-dihydroxy-4-methyl-3-oxabicyclo[12.4.0]octadeca-1(14),12,15,17-tetraene-2,8-dione.

Also known as: (4S,12E)-16,18-dihydroxy-4-methyl-3-oxabicyclo[12.4.0]octadeca-1(14),12,15,17-tetraene-2,8-dione, trans-Zearalenone, Zenone, F-2 toxin.

IUPAC name
(4S,12E)-16,18-dihydroxy-4-methyl-3-oxabicyclo[12.4.0]octadeca-1(14),12,15,17-tetraene-2,8-dione
CAS number
17924-92-4
Molecular formula
C18H22O5
Molecular weight
318.4 g/mol
SMILES
CC1CCCC(=O)CCCC=CC2=C(C(=CC(=C2)O)O)C(=O)O1
PubChem CID
5281576

Risk for dogs

Moderate risk

Dogs exposed to ZEN-contaminated grain-based pet food may develop hyperestrogenism: vulvar swelling and discharge in females, mammary gland development in males, and reproductive cycle disruption. Pet food recalls have included ZEN among the triggering mycotoxins. Dogs may eat moldy corn or corn-based food waste, creating acute exposure risk. The estrogenic effects in dogs can mimic ovarian cysts or pyometra, potentially leading to unnecessary veterinary procedures if ZEN exposure is not considered in the differential diagnosis. Clinical signs typically resolve after removing the contaminated food source.

Risk for cats

Moderate risk

Cats appear less sensitive to ZEN's estrogenic effects than dogs or pigs, likely due to metabolic differences in converting ZEN to the more potent alpha-zearalenol. However, contaminated cat food (grain-based dry food with poor-quality corn or wheat) can still deliver measurable ZEN doses. The primary concern is chronic low-level dietary exposure via grain byproducts. Cats with pre-existing reproductive system conditions may be more susceptible to hormonally active compounds. The co-occurrence of ZEN with OTA (hq-c-org-000056) in grain-based pet foods creates combined mycotoxin burden.

Regulatory consensus

2 regulatory and scientific bodies have classified Zearalenone. The classifications differ — that's the data.

AgencyYearClassificationNotes
EPA CTX / Genetox—Genotoxicity: negative (Ames: negative, 1 positive / 2 negative reports)
EPA CTX / Genetox—Genotoxicity: negative (Ames: negative, 1 positive / 2 negative reports)

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where pets encounter zearalenone

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Zearalenone:

  • Prevention (storage and agricultural practices)
    Trade-offs: Zero point-of-use emissions; shifts emissions to power generation (grid-dependent); lower operating cost; higher capital cost; infrastructure requirements (charging, grid capacity); rapidly improving economics.
    Relative cost: 1.2-2×

Frequently asked questions

Is zearalenone safe for pets?

Dogs exposed to ZEN-contaminated grain-based pet food may develop hyperestrogenism: vulvar swelling and discharge in females, mammary gland development in males, and reproductive cycle disruption. Pet food recalls have included ZEN among the triggering mycotoxins. Dogs may eat moldy corn or corn-based food waste, creating acute exposure risk. The estrogenic effects in dogs can mimic ovarian cysts or pyometra, potentially leading to unnecessary veterinary procedures if ZEN exposure is not considered in the differential diagnosis. Clinical signs typically resolve after removing the contaminated food source.

What products contain zearalenone?

Zearalenone appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments).

See Zearalenone in the pets app

Look up products containing zearalenone, compare to alternatives, and explore the full data record.

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Sources (3)
  1. EFSA Panel on Contaminants: Risks to Human and Animal Health from Zearalenone in Food and Feed (2017) — regulatory
  2. WHO Safety Evaluation of Certain Mycotoxins: Zearalenone (2000) — regulatory
  3. ASPCA Animal Poison Control Center: Mycotoxin Toxicosis in Companion Animals (2021) — report

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →