Pyrethrin/Pyrethroid Poisoning in Cats

pyrethrin-pyrethroid-poisoning-in-catsPyrethrin insecticides are naturally derived from the chrysanthemum (“mum”) flower, and pyrethroids are the synthetic versions. The formulations of these products vary in concentration, synergists, and carriers depending on their intended use, which may include:

  • Home and outdoor yard and garden insecticides (these typically come in liquids, sprays and foggers)
  • Over-the-counter medical flea shampoos
  • Topical flea and tick preventatives.


How toxic are these insecticides to dogs, cats and other animals?

Whether or not a pyrethrin or pyrethroid product is toxic depends on the animal species involved, as well as the concentration, synergists and carriers used in the product. The use of pyrethrins/pyrethroids is very safe in dogs; however, cats and fish are very sensitive to pyrethrins/pyrethroids.

Fish are so sensitive that they may die from even the smallest exposure, so be sure to cover aquarium tanks (with something non-porous like plastic wrap) or remove the tanks from an area you’ll be treating with a product containing a pyrethrin or pyrethroid (e.g., foggers, sprays, etc.). Likewise, if you apply a topical flea and tick spot-on onto your dog, do not allow him to jump into a body of water where fish may be living (for instance, a koi pond or a neighboring creek) for at least 24-48 hours following application.

Cats are also very sensitive to pyrethrins and pyrethroids because they’re unable to metabolize (break down) these agents quickly and efficiently due to their peculiar liver metabolism.  

How do cats become exposed to pyrethrin/pyrethroid insecticides?

Unfortunately, the most common way is due to owner error. Some cat owners mistakenly or purposely apply a dog flea and tick product (a high concentration pyrethrin/pyrethroid product) to their cats.

Canine/dog flea and tick topical spot-on products containing pyrethrins or pyrethroids should never be used on a cat without consulting your veterinarian. Double and triple-check what you are applying to, or using around, your cat at all times! Never apply a “small dog” flea and tick medication to a cat.

Cats can also be exposed under these other scenarios:

  • They live with a dog in close contact (e.g., grooming each other, sleeping next to each other, etc.) that’s recently been treated with a high concentration pyrethrin/pyrethroid flea and tick preventative designed for canines. Your best bet is to separate your dog from your cat until the flea-tick product is completely dry.
  • As many flea and tick shampoos or collars contain low concentrations of pyrethrins/pyrethroids, they should only be used as directed and kept in a closed, safe place away from cats. Flea and tick shampoos or collars specifically labeled for cats are safe to use.

How can I tell if my cat has pyrethrin/pyrethroid poisoning?

Signs of pyrethrin/pyrethroid toxicity in cats are serious and life-threatening, and can include all or any of the following listed. Any signs warrant an immediate visit to the veterinarian for further treatment

  • Excessive salivation/drooling
  • Agitation or restlessness
  • Vomiting
  • Hiding
  • Incoordination or difficulty jumping, standing or walking
  • Shaking
  • Twitching
  • Tremors
  • Seizures
  • Dyspnea (difficulty breathing)
  • Hypothermia or hyperthermia

Pyrethrin/pyrethroid toxicity is fatal for cats if not treated immediately.

What should I do if my cat is showing these symptoms?

If you suspect that your cat is having a severe reaction to a pyrethrin or pyrethroid, please bring your cat to your regular or emergency veterinarian immediately.

If you’re not sure what you’re seeing, call your veterinarian or Pet Poison Helpline, an animal poison control based out of Minneapolis, MN, USA* (800-213-6680) immediately. The sooner you seek treatment, the better the prognosis and outcome for your pet!

How does my veterinarian diagnose pyrethrin/pyrethroid poisoning?

Your veterinarian will make a presumptive diagnosis if there’s a known or possible history of exposure to a product containing a pyrethrin or pyrethroid, coupled with symptoms described above. If the symptoms are severe, your veterinarian will not wait to confirm the diagnosis before beginning treatment.

Is there an antidote for pyrethrin/pyrethroid poisoning in cats?

No. There is no antidote for pyrethrin or pyrethroid toxicity. However, quick and effective treatment with decontamination (e.g., bathing with liquid dish soap), anti-seizure drugs, muscle relaxants (e.g., methocarbamol), temperature monitoring, blood work (e.g., blood glucose) monitoring, and IV fluids are beneficial. This is why it’s so important to get help immediately.

How does my veterinarian treat severe pyrethrin/pyrethroid poisoning?

  • Once your cat is stable (i.e. not showing severe clinical signs), your veterinarian may start by bathing your cat with a liquid dish soap to prevent further exposure.
    If clinical signs/symptoms have developed, treatment will be based on the symptoms and route of exposure (skin, ingested, etc.). In all cases with the development of neurological signs (e.g., twitching, tremors, seizures), your cat will require hospitalization for typically 48 - 72 hours for monitoring and any supportive care that may be needed as symptoms can seem to resolve but then reoccur.
    In addition, your veterinarian’s team carefully monitors the cat’s temperature for an elevated or lowered reading. In most cases, the team will monitor blood work as well, to make sure blood sugar and kidney function remain normal.

What is the prognosis for recovery if a cat has severe pyrethrin/pyrethroid poisoning?

If your veterinarian has a chance to provide prompt, early treatment, the prognosis is generally good if the cat does not develop further complications secondary to neurological signs.

If the cat develops neurological signs that are uncontrolled or develops clotting problems or kidney failure secondary to severe seizures or hyperthermia, the prognosis is typically poor.

How can I prevent my cat from this poisoning?

  • Be very careful with topical flea and tick preventatives you’re applying to your cat! Only use cat products on cats. Remember, while dog preventatives are safe for dogs, they can be very dangerous to cats.  
  • To prevent accidental exposure, read the directions for any product carefully before use.
  • Keep your cat separate from any dogs that have been treated for 12-24 hours. This allows the product to dry thoroughly. When in doubt, a t-shirt can be applied to your dog to prevent accidental exposure to your cat until the product is dried.
  • Be cautious about the number of different flea/tick products used on your pet. If you have a flea infestation, please call your veterinarian about proper and safe treatment for your pets and environment.
  • Use the appropriate weight range for your cat. Do not use part of a larger size, or more than one smaller size, flea and tick preventative, as this may result in a poisoning. When in doubt, bring your cat to the veterinarian for a free “weigh-in!”
  • Store all pyrethrin or pyrethroid products safely and out of reach of your pets.
  • Never use a product on a pet that’s not intended to be used on animals! Even if the concentration of insecticide may be low, the carriers in such products may be harmful to animals.
  • Keep your cat away from any areas (indoors and out) that have been treated with a pyrethrin or pyrethroid product until it has completely dried.


With any poisoning, rapid diagnosis and treatment is imperative! It’s less dangerous to your pet, and less expensive for you to treat early.

pet_poison_hotline**Pet Poison Helpline, is an animal poison control service available 24 hours, 7 days a week for pet owners and veterinary professionals who require assistance treating a potentially poisoned pet. Pet Poison Helpline is available in North America by calling 800-213-6680. Additional information can be found online at www.petpoisonhelpline.com. Pet Poison Helpline is not directly affiliated with LifeLearn.

This client information sheet is based on material written by: Dr. Heather Handley, Staff Veterinarian, Pet Poison Helpline.

Updated, Ahna Brutlag, DVM, MS, DABT, DABVT, Associate Director of Veterinary Services, Pet Poison Helpline. © Copyright 2015 LifeLearn Inc. Used and/or modified with permission under license.

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