My Cat Had a Bad Reaction to Flea Treatment

Being a cat owner can be a wonderful experience, but it does come with a lot of responsibility. One responsibility is keeping your cat healthy by providing any necessary treatments, such as flea and tick medication. Unfortunately, it is possible that your cat can have a bad reaction to certain types of flea medications. Continue reading below to learn about the potential risks of flea medication and what to do if your cat experiences a negative reaction.

Potential Hazards of Flea Medications

Topical flea and tick medications contain active ingredients and a carrier that helps the product stay on your cat’s skin. If the product has not yet dried and your cat licks it off themselves or another animal, they can become hyperactive, agitated, nauseous, vomit, foam at the mouth, and salivate due to the bitter taste. You can combat this by giving your cat water and wet food or tuna to mask the taste. If you’re concerned about the product, you can give your cat a bath in liquid dish soap to remove it.

If you have a dog and you treated them with a Permethrin flea product or you accidentally applied a dog flea product to your cat, it is important to be aware of the potential risks. Permethrin is an insecticide used to repel or kill fleas and ticks. Permethrin is commonly found in dog flea products and unfortunately cats are highly sensitive to it. If your cat is not yet showing symptoms, you can bathe them in liquid dish soap three consecutive times to remove the product. If your cat exhibits tremors or seizures, you must take your cat to the veterinary clinic immediately. 

Potential Side Effects of Flea and Tick Medication 

If you applied a dog flea medication to your cat, they may have an adverse reaction to the product. Potential signs of poisoning you may see include:

  • Profuse drooling
  • Vomiting
  • Tremors
  • Hyperexcitability
  • Agitation
  • Seizures
  • Weakness
  • Difficulty breathing


If your cat is having a bad reaction to a flea product you’ve applied, you must remove the product immediately by bathing them in dish soap such as Dawn to get the substance off. Call Pet Poison Helpline at (855) 764-7661 and your veterinarian for immediate medical assistance. Take your cat to a veterinary clinic for professional treatment. It’s important to note that if your cat was exposed to pyrethrins/pyrethroids and is left untreated, fatality may occur. Always consult your veterinarian before administering any treatment to your pet and always double check the medication to make sure it is safe for them. Being extra careful will help you and your feline friend avoid any mishaps.