Get

In Your Inbox

Catster 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 I Use Dog Dewormer on Cats? Vet Reviewed Facts

Share

devon rex cat take medicine

Cats that have not received preventative treatment commonly contract worms, and although seeing the parasites in your cat’s vomit or stool is unpleasant and concerning, they are typically easy to treat. If you have a dog that recently had worms and have leftover dewormer medication, it’s natural to wonder if you can use it for your cat, too.

Some dewormers are safe to give to cats and dogs, but their dosages will differ. However, most dog dewormers aren’t suitable for cats, and vice versa. For that reason, it is recommended never to give dog dewormers to cats. Before giving your cat a dewormer, chat with a vet first.

Your cat should receive the dewormer best suited to their age, weight, and health condition. The medication should be given to your cat according to a vet’s instructions, which will differ from one pet to the other. Therefore, dewormers shouldn’t be shared between pets.

divider 3 paws

How Did My Cat Get Worms?

If your cat has worms, they’re not the exception since most cats contract worms at some point throughout their lives. Many kittens have worms because they are most vulnerable to parasites at such a young age. They can be born with them or get them from their mother’s milk.

Adult cats can also contract worms by coming in contact with the parasite’s eggs when walking through a contaminated area, sharing a litter box with an infected cat, touching or ingesting infected feces, or hunting and eating infected rodents. If a cat has walked through an infected area and the eggs or fecal particles get on their coat or paws, they can ingest them when they lick and groom themselves.

Although some worms are species-specific, others can infect your cats and dogs. Your cat can become infected by coming into contact with your dog’s poop as well as their fleas. If a flea from a dog jumps on your cat, hides in their coat, and gets ingested while grooming, they can develop a tapeworm infestation.

Cat with fleas
Photo Credit: Maja Marjanovic, Shutterstock

Are Worms Dangerous to Cats?

Several types of worms can infect your cat. Some cats may not show signs of having worms, while most will become sick. However, some species are life-threatening to cats. The severity of the worm infestation, as well as the health of a cat, can play a role in how sick they will become.

Intestinal worms are most dangerous to kittens because they can cause developmental issues, anemia, and intestinal obstructions, depending on the type of worms they have. Some worms, such as heartworms, threaten cats of all ages because they can cause damage to their heart and lungs.

Below are the types of worms and how they can affect your cat:

  • Roundworms: Can cause coughing, which can turn into pneumonia, vomiting, diarrhea, gas, an enlarged abdomen, weight loss, intestinal obstruction, and stunted growth.
  • Hookworms: May cause anemia, eczema, skin lesions, coughing, diarrhea with blood, weight loss, and poor appetite.
  • Whipworms: Can cause diarrhea with blood, weight loss, anemia, and dehydration.
  • Tapeworms: Can cause stunted growth, intestinal blockage, and digestive upset.
  • Lungworms: Can cause coughing, which can become pneumonia and lead to difficulty breathing.
  • Heartworms: Can cause coughing, rapid breathing, weight loss, vomiting, lethargy, seizures, and sudden death.
cats roundworms
Photo Credit: Todorean-Gabriel, Shutterstock

The Common Signs Among The Various Types of Worms

  • The presence of worms: Sometimes, you can see the worms or parts of the worms in your cat’s stool or vomit. You may also notice worms around their anus area.
  • A dull coat: Cats infested with worms often experience a change in their coat, where their once soft, silky, and shiny coat changes into a dull, dehydrated coat.
  • Pale gums: Anemia can cause your cat’s gums to become pale in color, whereas a healthy cat’s gums will be pink.
  • Digestive upset: Cats with worms often vomit and have diarrhea, which can have blood in it.
  • Weight loss: Although your cat might be eating more, they may still lose weight.

If you notice any of these signs in your cat, it’s essential to take them to the vet for an examination. The treatment is often straightforward, and the prognosis is typically good when treated early. However, if your cat doesn’t receive the care they need, they will suffer greatly, and it can even be fatal.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content for PangoVet2 save money

Can I Get Worms from My Cat?

If your cat has worms, you or other members of your household may have contracted worms, too. The most common way humans get worms from their cats is by walking in or touching contaminated soil. Cats often poop outside in the soil and sandboxes. If your child plays in their sandbox or you spend time gardening or walking around barefoot, you’re at risk of contracting worms.

The larvae in your cat’s poop can survive for a very long time, and the more an infected cat poops in your environment, the higher your risk of contracting worms. If you’ve dewormed your cat, you’re still at risk of contracting worms from another cat that uses your garden or sandbox as a toilet. Remember always to wash your hands and feet when gardening or walking barefoot outside.

divider 3 paws

How To Kill & Prevent Worms in Cats

The best way to protect your cat and yourself from contracting worms is to get them dewormed at an early age and repeat the treatment as frequently as the veterinarian advises. Your kitten can receive the deworming treatment from around 6 to 8 weeks of age and will likely need to be dewormed at least twice.

As your kitten gets older, they won’t need to be dewormed as frequently, but we recommend that you deworm your cat once every 1–3 months, especially if you allow them to roam outdoors or spend time with other cats and pets. Indoor cats without much exposure to the outdoors can safely be dewormed once every 3 months.

You can also lower your cat’s risk of contracting worms by starting them on flea and tick treatment, regularly cleaning and sanitizing their litter box, frequently changing out their old litter for new litter, and picking up the poop in the yard and sandbox with a shovel and discarding it properly.

divider 3 paws

Conclusion

Dog dewormers aren’t safe for cats because the dosage requirements differ. A cat is given a dewormer suitable for their age, weight, and health condition. Worms can be passed through the feces or fleas of one infected cat to another and from an infected dog. Worms can make a cat very sick, but with the correct treatment, they usually make a full recovery.

To prevent your cat from getting sick from worms, make sure to deworm them frequently. Outdoor cats should be dewormed around once a month, and indoor cats should be dewormed once every 3 months.


Featured Image Credit: Veera, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

Ask Dr. Paola – Help! My Male Cat Gets Into Fights! (March 9, 2026)

Welcome to our “Ask Dr. Paola” series, where every Monday we bring expert advice straight from Dr. Paola Cuevas (MVZ) to help our...

Why Your Cat’s Poop Smells Like a Biohazard

Nobody enjoys litter box duty, but sometimes it gets unbearable. The smell hits you from across the room. You’re scooping faster, lighting candles,...

RIP Your Furniture? Not With This Guide to Cat Scratch Damage Control

Your couch looks like it survived a minor apocalypse. The curtains have mysterious vertical shreds. That new rug you splurged on is already...

Celebrating 15 Years as the Most Popular Resident of No. 10 Downing Street

For almost 300 years, a rather unassuming Georgian building of black bricks with a shiny black door has been the official residence and...

More related

Top 10 Cutest Cat Videos of All Time

There’s no denying the fact that the internet loves cats. You can find an endless supply of viral videos that feature cats doing...

Dental Disease in Cats: Causes, Signs & Treatment Options (Vet Answer)

You may first notice bad breath, difficulty eating, or even bloody droplets in your cat’s food or water bowl. No matter how it...

Japanese Bobtail Cat Price: How Much They Cost in 2026

Japanese Bobtail cats are friendly, generally healthy, and low maintenance. They are playful companions but like all pets, have their share of expenses...

Ask Dr. Paola – Help! My Kitten Pukes After She Eats! (March 2, 2026)

Welcome to our “Ask Dr. Paola” series, where every Monday we bring expert advice straight from Dr. Paola Cuevas (MVZ) to help our...

Keep reading

How Often Do Cats Need Rabies Shots? Vet Approved Facts & FAQ

Several vaccinations are necessary for your cat to ensure a healthy lifestyle. There are various core vaccines, those that are recommended based on lifestyle, and many that require boosters to stay effective. With so much to keep track of, it...

Veterinarian at vet clinic giving injection to cat

Can Cats Eat Shrimp? Vet-Reviewed Facts & FAQ

So, you know your cat loves fish, but she seems to be drawn to that shrimp you’re enjoying. Naturally, this will lead to your wondering if cats can eat shrimp. Is shrimp safe for your cat to eat? The short...

Can Cats Eat Shrimp

Is Sedum Poisonous to Cats? Common Houseplants Examined & Vet-Reviewed

When it comes to succulents and cats, you can never be too careful. The last thing you want is something growing in your garden or that you bring into your home to make your furry friend sick or worse. Luckily,...

Catster_Is Sedum Poisonous to Cats

How Long Can You Safely Leave Your Cat Alone? Vet Approved Tips & Alternatives

Many of us cat owners need to leave our cats alone on a regular basis. But where’s the line between an okay amount of time for your cat to be left alone and too long? The answer depends on the...

fluffy cat lying on windowsill

Is It True That All Cats Have Carpal Whiskers on Their Legs? Feline Anatomy Explained

There’s no question that cats are unbelievably adorable. Everything from their gorgeous eyes to their tiny little paws is nothing short of cuteness galore. But one often overlooked feature that adds to this cuteness is the whiskers. Everyone knows that...

Close up to a ginger cat paws and claws scratching carpet

Why Do Cats Like Hiding in Dark Places? 5 Vet-Reviewed Reasons

Cats love to hide behind furniture, in boxes, and under just about any object they can fit beneath. They are so stealthy you may find yourself shaking a bag of treats just to ensure they’re still in your house! But...

cat hiding in a dark place

Why Does My Cat Lay on My Chest? 5 Vet-Reviewed Reasons for This Behavior

Why does my cat lay on my chest? It’s a common question from cat parents everywhere, and for good reason. If you’re lying on the couch reading a book or watching a movie, many cats will take the opportunity to...

Child playing with cat at home

TEEF for Life Protektin30™ Review 2026: Our Hands-On Experience

It’s a fact: Cats do not like having their teeth brushed. But it’s also true that poor dental health can dramatically shorten your cat’s lifespan. So what’s a kitty owner to do? TEEF for Life says they have the solution....

TEEF for Life Review 2024 - featured image

Love Cats? So Do We! Join the Catster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Catster Email Newsletter

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.