d-trans-Allethrin
Cyclopropanecarboxylic acid, 2,2-dimethyl-3-(2-methyl-1-propenyl)-, (1S)-2-methyl-4-oxo-3-(2-propenyl)-2-cyclopenten-1-yl ester, (1R,3R)-
EPA Substance Registry Services (SRS) listed active ingredient for pesticide products.
Safety around dogs & cats
Cats cannot efficiently glucuronidate pyrethroids, so d-trans-allethrin is a real feline hazard even though its mammalian toxicity is otherwise low (ASPCA, Pet Poison Helpline, VCA, MSPCA-Angell); small exposures can cause drooling, tremors, and neuroexcitation. Keep cats away from mats, coils, and cartridges and never let one mouth the source. Dogs are far more tolerant (Merck Veterinary Manual). Keep pet birds out of enclosed treated spaces, and never apply to any animal.
High confidence. Ratings from ASPCA Animal Poison Control, the Pet Poison Helpline, and published veterinary toxicology. This is general information, not veterinary advice. If your pet is exposed, call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435.
The evidence
- Field evaluation of an area repellent system (Thermacell) against Phlebotomus papatasi and Ochlerotatus caspius in Sanliurfa Province, Turkey2003Field TrialWell-supported evidence
This was an outdoor field trial of the Thermacell area repellent, the butane-heated device that warms a mat holding allethrin so it drifts into the surrounding air. Researchers ran it in a village in Sanliurfa Province in southeastern Turkey and measured how much it cut biting from two different pests at once: Phlebotomus papatasi, a sand fly that spreads leishmaniasis, and Ochlerotatus caspius, a floodwater mosquito. Volunteers acted as bite collectors so the team could compare landing and biting rates with the device running versus without it.
Products using it
Regulatory notes
Source: EPA SRS active ingredient list export. Minimum risk (25(b)) status is applied separately when applicable.