Pyrethrins
Pyrethrins and Pyrethroids
EPA Substance Registry Services (SRS) listed active ingredient for pesticide products.
Safety around dogs & cats
Cats are highly sensitive to pyrethrins because they cannot efficiently glucuronidate them; the ASPCA, Pet Poison Helpline, VCA, and MSPCA-Angell all note that even small exposures can trigger drooling, tremors, and neuroexcitation in cats. Dogs tolerate them well at normal exposures (Merck Veterinary Manual). Do not let a cat mouth a coil or cartridge, 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
Pyrethrins are fast-acting botanical insecticides used in coils and space sprays. They knock down and kill mosquitoes on contact, with coil and fogging studies showing high short-term knockdown, but they break down quickly in air and light and leave little residual, so protection is brief.
- Environmental health risks and benefits of the use of mosquito coils as malaria prevention and control strategy2018ReviewWell-supported evidence
The mosquito coil is the oldest and cheapest airborne repellent device, a spiral you light so that it smolders and releases a pyrethroid such as allethrin or pyrethrins into the air. This review weighed both sides of the coil: how much it actually protects against mosquitoes, and what the smoke does to the people breathing it. It is a helpful reality check for anyone reaching for coils as a low-cost area repellent, because it puts modest efficacy next to a real air-quality cost.
- Field Evaluation of Indoor Thermal Fog and Ultra-Low Volume Applications For Control of Aedes aegypti in Thailand2017Field TrialWell-supported evidence
Field comparison of thermal fog and ULV pyrethrin space spray against Aedes aegypti.
- A systematic review of mosquito coils and passive emanators: defining recommendations for spatial repellency testing methodologies2012ReviewWell-supported evidence
Systematic review of the spatial repellency of mosquito coils and passive emanators.
- Efficacy of mosquito coils containing 0.3% and 0.4% pyrethrins against An. gambiae sensu lato mosquitoes1998LabLimited evidence
Chamber knockdown and mortality assay of pyrethrins coils against Anopheles gambiae.
Regulatory notes
Source: EPA SRS active ingredient list export. Minimum risk (25(b)) status is applied separately when applicable.