Is permethrin toxic to cats?
Also called: permethrin, dog flea treatment, dog flea spot-on, flea spot on for dogs, pyrethroids, pyrethrins, flea and tick treatment for dogs, cypermethrin
Toxic
Found in many dog flea spot-ons. Even a small amount can seriously poison a cat.
Yes, very. Permethrin is in many flea and tick spot-ons made for dogs. Even a small amount, put on a cat or picked up by touching a treated dog, can cause tremors, seizures and death.
Signs to watch for
- Severe drooling, tremors and seizures that can be life-threatening.
Why it's dangerous
- A cat's liver can't break permethrin down into a harmless form, so it builds up in the body.
How cats get exposed
- Dog products used on catsNever use a dog flea product on a cat, even in a smaller amount.
- Contact with a treated dogCats can be poisoned by rubbing against a treated dog, sitting on the same furniture, or licking the product off it.
- Keeping them apartIf your dog is treated with a permethrin product, keep your dog and cat apart for 72 hours.
Where this comes from
International Cat Care
even a very small amount of permethrin can make a cat seriously ill.
Checked 9 October 2026
Pet Poison Helpline
Concentrated topical flea and tick medications made for dogs contain pyrethrins or pyrethroids, which are highly toxic to cats.
Read "List of Things Toxic to Cats"
Checked 9 October 2026
Where this comes from
International Cat Care
Exposure to high doses of permethrin, often found in spot-on dog flea treatments, can result in serious illness in cats and even death.
even a very small amount of permethrin can make a cat seriously ill.
When a cat rubs against a dog, or even sits on the same furniture, permethrin can transfer to the cat’s coat and cause poisoning.
Checked 9 October 2026
Pet Poison Helpline
Symptoms of poisoning include severe drooling, tremors, and potentially life-threatening seizures.
Read "List of Things Toxic to Cats"
Checked 9 October 2026
Where this comes from
International Cat Care
if your cat has been in contact with a dog treated with permethrin, contact your veterinary team immediately.
Checked 9 October 2026
Where this comes from
Pet Poison Helpline
Symptoms of poisoning include severe drooling, tremors, and potentially life-threatening seizures.
Read "List of Things Toxic to Cats"
Checked 9 October 2026
Where this comes from
International Cat Care
A cat’s liver can’t break down certain chemicals into a harmless form, and so the harmful chemical builds up in the cat’s body
Checked 9 October 2026
Where this comes from
International Cat Care
Dog flea products should never be used on cats .
Checked 9 October 2026
International Cat Care
even a very small amount of permethrin can make a cat seriously ill.
Checked 9 October 2026
Where this comes from
International Cat Care
When a cat rubs against a dog, or even sits on the same furniture, permethrin can transfer to the cat’s coat and cause poisoning.
Checked 9 October 2026
Pet Poison Helpline
Cats can be poisoned if pet owners apply dog insecticides on them, or if they lick the medications off dogs.
Read "List of Things Toxic to Cats"
Checked 9 October 2026
Where this comes from
International Cat Care
If you choose to use a permethrin-based product for your dog, keep your dog and cat apart for 72 hours
Checked 9 October 2026
Where this comes from
International Cat Care
If you choose to use a permethrin-based product for your dog, keep your dog and cat apart for 72 hours
Checked 9 October 2026
Cornell Feline Health Center
Cats must not be allowed to come in contact with a treated dog for 24 hours
Checked 9 October 2026