Pet Safety / Compounds / d-Phenothrin

Is d-Phenothrin safe for dogs and cats?

Low risk for pets

d-Phenothrin-containing flea and tick products are widely marketed and approved for use on dogs; dogs tolerate the compound well at label doses. The primary dog-specific concern is ensuring that products with higher d-phenothrin concentrations labeled for dogs only are not applied to cats.

What is d-phenothrin?

The IUPAC name is (3-phenoxyphenyl)methyl 2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropane-1-carboxylate.

Also known as: (3-phenoxyphenyl)methyl 2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropane-1-carboxylate, phenothrin, Sumithrin, Phenoxythrin.

IUPAC name
(3-phenoxyphenyl)methyl 2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropane-1-carboxylate
CAS number
26002-80-2
Molecular formula
C23H26O3
Molecular weight
350.4 g/mol
SMILES
CC(=CC1C(C1(C)C)C(=O)OCC2=CC(=CC=C2)OC3=CC=CC=C3)C
PubChem CID
4767

Risk for dogs

Low risk

d-Phenothrin-containing flea and tick products are widely marketed and approved for use on dogs; dogs tolerate the compound well at label doses. The primary dog-specific concern is ensuring that products with higher d-phenothrin concentrations labeled for dogs only are not applied to cats.

Risk for cats

High risk

d-Phenothrin is a type I pyrethroid — cats are sensitive with T-syndrome risk. Of particular concern: combination flea spray products containing d-phenothrin plus methoprene (Zodiac, Hartz) have been implicated in cat toxicosis events; the products are labeled for use on cats at specific concentrations, but off-label application (dog products applied to cats, or spray products used at higher doses) causes toxicosis. Additionally, NYC aerial spraying for West Nile virus mosquito control (Sumithrin-based) during early 2000s led to documented cat toxicosis reports when outdoor cats were exposed during fogging operations. The widespread consumer flea product use increases the likelihood of accidental overexposure compared to purely agricultural pyrethroids.

Regulatory consensus

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

AgencyYearClassificationNotes
EPA CTX / Genetox—Genotoxicity: negative (Ames: None, 0 positive / 2 negative reports)
EPA CTX / Genetox—Genotoxicity: negative (Ames: None, 0 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 d-phenothrin

  • 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 d-Phenothrin:

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

Frequently asked questions

Is d-phenothrin safe for pets?

d-Phenothrin-containing flea and tick products are widely marketed and approved for use on dogs; dogs tolerate the compound well at label doses. The primary dog-specific concern is ensuring that products with higher d-phenothrin concentrations labeled for dogs only are not applied to cats.

What products contain d-phenothrin?

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

See d-Phenothrin in the pets app

Look up products containing d-phenothrin, 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 →