Pet Safety / Compounds / Fenbendazole

Is Fenbendazole safe for dogs and cats?

Low risk for pets

Safe-Guard/Panacur is labeled for dogs at 50 mg/kg/day for 3 consecutive days. Excellent safety margin (LD50 >10,000 mg/kg). Effective against roundworms, hookworms, whipworms, tapeworms, and Giardia.

What is fenbendazole?

Also known as: Panacur, Safe-Guard, Fenbenol, Hoechst 33258.

CAS number
43210-67-9
Molecular formula
C15H13N3O2S
Molecular weight
299.35 g/mol
SMILES
COC(=O)NC1=NC2=C(N1)C=C(C=C2)SC3=CC=CC=C3
PubChem CID
3334

Risk for dogs

Low risk

Safe-Guard/Panacur is labeled for dogs at 50 mg/kg/day for 3 consecutive days. Excellent safety margin (LD50 >10,000 mg/kg). Effective against roundworms, hookworms, whipworms, tapeworms, and Giardia.

Risk for cats

Low risk

Used off-label in cats at 50 mg/kg/day for 3-5 days. Well-tolerated. Occasionally used for Giardia treatment.

Regulatory consensus

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

AgencyYearClassificationNotes
FDA CVM1983Approved for use in dogs, cattle, horses, swine, game birds
EU/EMA2010MRL established for food-producing animals (Regulation 37/2010)

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 fenbendazole

  • Veterinary Medicine
  • Food
  • Off Label Human Use

Safer alternatives

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

  • Mebendazole
    Trade-offs: FDA-approved for human use. Same benzimidazole class. Better human pharmacokinetic data. Also under cancer investigation.
    Relative cost: Higher (human formulation)

Frequently asked questions

Is fenbendazole safe for pets?

Safe-Guard/Panacur is labeled for dogs at 50 mg/kg/day for 3 consecutive days. Excellent safety margin (LD50 >10,000 mg/kg). Effective against roundworms, hookworms, whipworms, tapeworms, and Giardia.

See Fenbendazole in the pets app

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

Open in pets View raw API data

Sources (2)
  1. FDA Green Book — Fenbendazole Approvals — fda
  2. Fenbendazole as anti-cancer agent — preclinical evidence — pubmed

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 →