Hepper is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Can You Use Dog Dewormer on Cats? Vet Reviewed Explanation

Jessica Kim

By Jessica Kim

infusion of liquid medicine by a vet from a syringe into the mouth of a cat

Vet approved

Dr. Amanda Charles Photo

Reviewed & Fact-Checked By

Dr. Amanda Charles

Veterinarian, BVSc GPCert (Derm) MRCVS

The information is current and up-to-date in accordance with the latest veterinarian research.

Learn more »

While deworming medications for cats and dogs may contain similar ingredients, it’s not a good idea to use dog dewormers on your cat. This is because they contain varying levels of active ingredients, as well as the dosing amount varying depending on the size of the pet. You will only find a small amount of antiparasitic treatments that are the same for both dogs and cats, most dewormers are pet specific for a reason!

Always consult with your veterinarian and follow their advice to choose the correct worm treatment for your cat.  So, if you live with both cats and dogs, it’s important to keep their dewormer medication separate and make sure to give them the correct ones.

Reasons Not to Give Cats Dog Dewormers

Parasitic worms can be frustrating as they’re easily passed on from one pet to another, and humans are also susceptible to contracting some of them. There are instances when your dog may have gotten dewormer medication, and you have leftover medication. It may seem convenient to use the same medication on your cat if they also get worms. However, this can end up being harmful to your cat for several reasons and should be avoided at all costs.

Image Credit: Rattiya Thongdumhyu, Shutterstock

Different Dosages

First, cats and dogs require different dosages. Even smaller dogs may still require a different dosage of active ingredients than cats. So, cats can end up getting overmedicated. They can start to feel sick or get certain side effects associated with dewormer medication, like diarrhea, lack of appetite, salivating, and vomiting

In more severe cases, cats can develop kidney or liver disease. So, it’s vital that they’re taking the correct dosage.

Different Worms

Cats can get different types of worms including roundworms, tapeworms, hookworms and heartworms.  While it’s certainly possible that your dog can transfer some kinds of worms to your cat, there’s still the chance that your cat contracts something different.

The type of medication your cat needs will depend on the type of worm. So, it’s possible that you may end up giving your cat medication that isn’t appropriate or effective for their worm infection.


Some cats may be allergic to certain medications including dewormers. So, if you give your cat medication prescribed for your dog, and it ends up having a reaction, you can end up with more issues than you started with. Severe anaphylactic reactions are luckily rare in pets, but some other signs of a possible drug allergy include:

  • Lethargy
  • Facial swelling
  • Hives
  • Itchy skin
  • Loss of appetite
  • Vomiting

How to Deworm Your Cat

giving cat a pill
Image Credit: Dora Zett, Shutterstock

Because of complications that can occur with feeding cats the wrong deworming medication, it’s important to never give your cat dewormers without consulting your veterinarian first. Cats can display certain warning signs that they have worms:

  • Breathing issues/coughing
  • Diarrhea
  • Distended abdomen
  • Poor skin and coat condition
  • Weight loss
  • Worms in stool

You can find some homemade remedies or natural remedies that claim to treat worms. However, the most effective and efficient way to get rid of worms is to receive a dewormer regimen from your veterinarian. Your veterinarian will determine the correct type of medication for your cat to take depending on the signs they are showing and the worms they have been diagnosed with.

Some dewormers may require multiple administrations before your cat is worm-free. So, it’s important to follow your veterinarian’s exact instructions to ensure the worms stay away for good. Once your cat completes its dewormer regimen, your veterinarian may prescribe preventative medication to protect your cat from future worm infestations.


It’s fairly common for cats to contract worms, and it’s extremely important to give your cat the correct dewormer medication for treatment. Never give your cat a dog dewormer. Taking the essential step of consulting your veterinarian will ensure that your cat becomes worm-free as quickly as possible and doesn’t take an overdose of medication.

Featured Image Credit: Zhuravlev Andrey, Shutterstock

Jessica Kim

Authored by

Jessica is a freelance writer who spends most of her day researching and writing while her fluffy Cavapoo, Nora, naps beside her. She loves and appreciates pets and animals because there’s so much to learn from them, and they do so much for people. As a dog mom, she understands the special connection that pet parents have with their pets. So, she loves sharing helpful information that people can use to better understand...Read more

Related Articles

Further Reading

Vet Articles

Latest Vet Answers

The latest veterinarians' answers to questions from our database