Pyrethrin Toxicity in Cats

Pyrethrins can make your itty bitty kitty very sick. Your adult cat, too.
i John Foxx/Stockbyte/Getty Images

Insecticides can be dangerous any time they're not used right, but pyrethrins and cats are an especially dangerous combination. Cats simply can't handle more than very tiny amounts of pyrethrin, and the toxic reaction can be severe.

Pyrethrins and Permethrin

Pyrethrins are a natural substance extracted from chrysanthemums. If you use them in the right strength and amount, they are generally safe for your cat. Permethrins are the man-made version of pyrethrins. They are usually very concentrated, and although they are safe for dogs, they are usually too potent for cats. In addition, your cat's liver cannot process either pyrethrins or permethrins easily, so the chance of poisoning is high.


Both pyrethrins and permethrins kill fleas and ticks. They are the active ingredient in many flea sprays, shampoos, powders, collars and spot application treatments. Pyrethrins are in some garden pest control products, home foggers and commercial farming operations.

Toxic Exposure

Most pyrethrin poisoning happens when a well-meaning owner uses too much of a pyrethrin-based product or uses one that is too strong for a cat. Kittens, elderly cats and underweight cats are even more susceptible to pyrethrin toxicity. This is because their bodies can't process the chemical as well, and the lack of a protective layer of fat allows the chemical to soak right into muscles and tissues.


It can take up to 24 hours after exposure for your cat to show signs of poisoning, though symptoms can start right away. Drooling and tremors are among the first signs you will probably notice. Your kitty will probably also be agitated or nervous and may be weak or have trouble breathing. Vomiting is also a sign of pyrethrin poisoning.


Pyrethrin poisoning can kill your cat. If you notice tremors or other signs of poisoning, t's important to get treatment right away. Your veterinarian will probably give intravenous or subcutaneous fluids as well as medications to stop seizures and tremors. Your kitty may need to stay at the clinic or emergency hospital for a couple days until the tremors stop.


The easiest way to keep your cat from getting poisoned by pyrethrins is to carefully follow the manufacturer's instructions for all products that contain them. Never use treatments meant for dogs on your cat. Pay attention to age restrictions if you have a young kitten; consult your vet before administering toxic medicines to a senior dog. Also, watch for second-hand poisoning: Make sure your cat doesn't groom or snuggle up to your dog who was just treated with a flea preventative.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

the nest