Pet Safety / Compounds / Cyfluthrin

Is Cyfluthrin safe for dogs and cats?

Low risk for pets

Dogs tolerate cyfluthrin well at consumer product use concentrations; label instructions for dog safety include ventilating spaces after fogging and not allowing dogs into treated areas until surfaces are dry. High-dose scenarios (direct spraying of a dog, ingestion of undiluted product) can produce mild tremors; supportive care generally sufficient.

What is cyfluthrin?

The IUPAC name is [cyano-(4-fluoro-3-phenoxyphenyl)methyl] 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylate.

Also known as: [cyano-(4-fluoro-3-phenoxyphenyl)methyl] 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylate, Cyfoxylate, Baythroid, Solfac.

IUPAC name
[cyano-(4-fluoro-3-phenoxyphenyl)methyl] 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylate
CAS number
68359-37-5
Molecular formula
C22H18Cl2FNO3
Molecular weight
434.3 g/mol
SMILES
CC1(C(C1C(=O)OC(C#N)C2=CC(=C(C=C2)F)OC3=CC=CC=C3)C=C(Cl)Cl)C
PubChem CID
104926

Risk for dogs

Low risk

Dogs tolerate cyfluthrin well at consumer product use concentrations; label instructions for dog safety include ventilating spaces after fogging and not allowing dogs into treated areas until surfaces are dry. High-dose scenarios (direct spraying of a dog, ingestion of undiluted product) can produce mild tremors; supportive care generally sufficient.

Risk for cats

Extreme risk

Cyfluthrin is a type II alpha-cyano pyrethroid with extreme feline toxicity; household use products (Bayer Advanced Pest Control, Home Pest sprays) applied indoors have caused fatal toxicosis in cats through contact with treated surfaces or inhalation of aerosols. The CS syndrome in cats involves intense hypersalivation, myoclonus, generalized seizures, and severe hyperthermia. Cyfluthrin concentrations in consumer fogger products ('bug bombs') can be high enough to deposit toxic residues on all household surfaces; cat owners must remove pets before fogging and ventilate thoroughly before re-entry.

Regulatory consensus

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

AgencyYearClassificationNotes
EPA CTX / EPA OPP—Not Likely to Be Carcinogenic in Humans
EPA CTX / Genetox—Genotoxicity: negative (single report) (Ames: None, 0 positive / 1 negative reports)
EPA CTX / Genetox—Genotoxicity: negative (single report) (Ames: None, 0 positive / 1 negative reports)
US_EPA2024registered_restrictedEPA restricted-use pyrethroid.

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 cyfluthrin

  • 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 Cyfluthrin:

  • Physical/mechanical pest control (IPM)
    Trade-offs: More labor-intensive. May not be sufficient for severe infestations.
    Relative cost: 1.2-2×
  • Spinosad
    Relative cost: 1.2-2×
  • Essential oil sprays
    Relative cost: 1.2-2×
  • IPM
    Relative cost: 1.2-2×

Frequently asked questions

Is cyfluthrin safe for pets?

Dogs tolerate cyfluthrin well at consumer product use concentrations; label instructions for dog safety include ventilating spaces after fogging and not allowing dogs into treated areas until surfaces are dry. High-dose scenarios (direct spraying of a dog, ingestion of undiluted product) can produce mild tremors; supportive care generally sufficient.

What products contain cyfluthrin?

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

Why do regulators disagree about cyfluthrin?

Cyfluthrin has been classified by 4 agencies including EPA CTX / EPA OPP, EPA CTX / Genetox, EPA CTX / Genetox, US_EPA, with differing conclusions. 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. See the regulatory consensus table on this page for the full picture.

See Cyfluthrin in the pets app

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

Open in pets View raw API data

Sources (2)
  1. US EPA Pyrethroid Reregistration Eligibility Decision — cypermethrin/deltamethrin/lambda-cyhalothrin/bifenthrin/cyfluthrin/fenvalerate/tau-fluvalinate/fenpropathrin; type I/II classification; aquatic toxicity; cat sensitivity; sodium channel mechanism; human paresthesia; buffer zones (2011) (2011) — regulatory
  2. ASPCA Animal Poison Control Center: Pyrethroid Toxicosis in Cats and Dogs — type I vs type II CS/T syndromes; extreme cat sensitivity (sodium channel/UGT deficiency); bathing decontamination; methocarbamol tremor control; cyproheptadine; lipid emulsion severe cases (2023) (2023) — veterinary

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 →