Cat Has Worms: What to Do and How to Treat

Name: Cat Has Worms: What to Do and How to Treat
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-02

If your cat has worms, the first thing to do is collect a fresh stool sample and call your veterinarian. Most intestinal worms in cats are treatable with prescription dewormers, but the right drug depends on which worm your cat has. This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

Do not buy a generic dewormer and guess. Different worms need different drugs, and the wrong product wastes time and money.
Bring a fresh fecal sample (less than 24 hours old) to your vet so they can identify the parasite.
If you see worms in vomit or stool, save them in a sealed bag or jar and bring them along.
Treat all cats in the household at the same time, because worms spread easily between cats.
Wash your hands after handling your cat, its litter box, or its bedding, since some cat worms can infect people.

What "Worms" Really Means in Cats

"Worms" is a catch-all word for intestinal parasites. The most common ones in cats are roundworms, hookworms, and tapeworms. Coccidia and Giardia are not worms at all, they are single-celled parasites, but owners often lump them together because the symptoms look similar.

A large European survey of over 2,200 cats found intestinal parasites in 30.6% of the animals tested [1]. The most common was Toxocara cati, a roundworm, found in 13.6% of cats [1]. Giardia came next at 11.9%, followed by Cystoisospora felis at 7.2% [1]. Shelter cats had a higher rate, 40.3%, compared with owned cats at 29.5% [1].

A separate study of young cats with diarrhea found that 33.9% tested positive for coccidia, mostly Cystoisospora felis [2]. That study also found that cats with coccidia and roundworms, or with hookworms and Giardia, were more likely to have severe diarrhea [2].

There is also a rare skin worm called Dracunculus insignis. It lives under the skin, mostly on the legs, and female worms can grow longer than 1 foot (300 millimeters) [3]. Cats pick it up by drinking contaminated water or eating an infected frog, and it is only occasionally seen in cats living near shallow, stagnant water [3].

Signs Owners Notice

Some cats with worms show no signs at all. Others show a mix of the following:

A potbelly, especially in kittens
Weight loss or a dull coat
Diarrhea or soft stool
Vomiting, sometimes with visible worms
Scooting the rear end on the floor
Small white segments that look like grains of rice near the tail or in the litter box
Worms that look like spaghetti in stool or vomit

If your cat has diarrhea along with worms, see Cat Diarrhea with Worms: Causes and Treatment Options for a closer look at what that combination means.

Do not confuse intestinal worms with ringworm. Ringworm is a fungal skin infection, not a worm, and it needs a completely different treatment. If you are seeing crusty, circular bald patches on the skin, read How To Treat My Cats Ringworm At Home instead.

Causes and Risk Factors

Worms spread in several ways.

Roundworms. Kittens can get roundworms from their mother before birth or through her milk. Adult cats get them by eating infected rodents or by contact with contaminated soil.

Hookworms. These worms can burrow through the skin or be swallowed. They live in the small intestine and feed on blood, so heavy infections can cause anemia.

Tapeworms. The most common tapeworm in cats, Dipylidium caninum, spreads when a cat swallows an infected flea. Another tapeworm, Hydatigera taeniaeformis, spreads when a cat eats an infected rodent. A study that used necropsy as the gold standard found H. taeniaeformis in 4 out of 35 cats, and D. caninum in 2 out of 35 cats [4]. That same study showed that standard stool tests miss many tapeworm infections, so a negative fecal test does not always rule tapeworms out [4].

Coccidia and Giardia. These spread through contaminated water, food, and litter boxes. They are more common in crowded settings like shelters and catteries.

Outdoor access, hunting, flea infestations, and living with other cats all raise the risk. Kittens and senior cats tend to get hit hardest.

How Vets Diagnose Worms

Your veterinarian will start with a fecal flotation test, which separates parasite eggs from stool so they can be seen under a microscope. They may also use a Giardia-specific test or a PCR test, which looks for parasite DNA.

Because tapeworm eggs are shed intermittently, stool tests can miss them [4]. If your vet sees tapeworm segments on your cat's rear end or in the litter box, that alone can confirm the diagnosis.

For kittens, your vet may recommend deworming before vaccinations. A 2024 study looked at whether intestinal parasites affect vaccine response in kittens and compared the antibody response to feline panleukopenia virus vaccination in kittens with and without intestinal parasites [5]. Ask your vet how they want to sequence deworming and vaccines for your kitten.

How to Treat a Cat for Worms

Treatment depends on the worm. There is no single product that covers everything.

Worm type	Typical treatment approach	Notes
Roundworms	Prescription dewormer, often repeated in 2 to 3 weeks	Kittens often need several rounds
Hookworms	Prescription dewormer, sometimes with iron support if anemic	Repeat fecal test after treatment
Tapeworms	Drug that targets tapeworms, plus flea control	Treating fleas is essential to stop reinfection
Coccidia	Prescription anticoccidial drug	Not a worm, so dewormers do not work
Giardia	Prescription antiprotozoal drug, plus bathing	Sanitation at home matters a lot
Skin worm (D. insignis)	Veterinary removal or targeted treatment	Rare, and needs a vet's assessment [3]

Your veterinarian calculates the dose from your cat's weight and health. Never split a dog dewormer for a cat, and never guess at a dose. Some dewormers that are safe for dogs are toxic to cats.

For kittens, treatment is usually started early and repeated on a schedule. A kitten with a potbelly, diarrhea, or poor growth needs to be seen promptly. If you are asking "my kitten has worms what do I do," the answer is the same as for an adult cat: get a fecal test and use prescription medication. Do not use over-the-counter products on a kitten without veterinary guidance, because the dose depends on weight and age.

If you also have a dog with worms, the treatment plan is different. See Dog Diarrhea with Worms: What to Do and How to Treat for the canine side.

What to Do If Your Cat Vomits Worms

If your cat vomits worms, stay calm. This usually means a heavy roundworm burden, and the worms are moving up from the small intestine into the stomach.

Pick up the worms with a paper towel or gloves, place them in a sealed plastic bag, and bring them to your vet. Do not handle them with bare hands. Wash your hands thoroughly afterward.

Call your vet the same day. Vomiting worms is not an emergency by itself, but it means the infection is significant and treatment should start soon. If your cat is also lethargic, refusing food, or vomiting repeatedly, that is more urgent.

If your cat vomits worms at home and seems otherwise fine, you can wait for a same-day appointment. If your cat is weak, dehydrated, or has blood in the vomit, go to an emergency clinic.

Recovery, Outlook, and Long-Term Management

Most cats improve quickly once they start the right medication. Diarrhea and vomiting often settle within a few days, though a full recovery can take one to two weeks depending on the worm and how long the infection lasted.

Your vet will likely want a follow-up fecal test a few weeks after treatment to confirm the worms are gone. Tapeworms and Giardia in particular can be stubborn, and repeat treatment is common.

Kittens need extra attention. They have less reserve than adult cats, and heavy worm burdens can stunt growth. Keep them warm, offer small frequent meals, and follow your vet's deworming schedule closely.

Long term, the goal is prevention. A cat that hunts or goes outside will always have some exposure risk, so routine testing matters.

Prevention

Prevention comes down to a few habits.

Have your cat's stool tested at least once a year, and more often if you have kittens or an outdoor cat [6].
Keep your cat on year-round flea control, since fleas carry tapeworms.
Clean the litter box daily and wash your hands afterward.
Dispose of cat feces in sealed bags, not in the garden or compost.
Keep cats indoors when possible to reduce hunting and exposure.
Wash food and water bowls regularly, and do not let your cat drink from ponds or stagnant water [3].
Deworm kittens on the schedule your vet recommends.

If you have young children or anyone with a weakened immune system at home, tell your vet. Some cat parasites can infect people, and extra precautions may be needed.

Limitations and When to Contact a Veterinarian

This article covers general information only. Your cat's individual case needs a veterinarian who can examine it, test its stool, and prescribe the right treatment.

Contact your vet the same day if:

Your cat vomits worms
You see worms in the stool
Your kitten has a potbelly, diarrhea, or is not gaining weight
Your cat has diarrhea lasting more than 24 hours

Go to an emergency clinic now if:

Your cat is weak, collapsed, or unresponsive
There is blood in the vomit or stool
Your cat is straining to defecate with no result
Your kitten is dehydrated, cold, or refusing to eat

Schedule a routine visit if:

Your cat has no symptoms but has not had a fecal test in over a year
You have a new kitten or a new cat in the home
You notice scooting, a dull coat, or mild weight loss

Frequently Asked Questions

Can I treat my cat for worms at home?

Only with a prescription from your veterinarian. Over-the-counter dewormers often target the wrong parasite or contain doses that are unsafe for cats. Your vet will identify the worm first, then choose the right drug and dose.

Are cat worms contagious to people?

Some are. Roundworm larvae can cause serious disease in humans, especially children, and hookworms can burrow into human skin. Good hand hygiene and prompt litter box cleaning lower the risk a lot.

How long does worm treatment take to work?

Most cats start feeling better within a few days. Full clearance usually takes one to two weeks, and your vet may want a follow-up stool test to confirm the worms are gone.

Do indoor cats need worm prevention?

Yes. Indoor cats can still pick up worms from fleas, from soil tracked in on shoes, or from a new kitten or cat in the home. Yearly fecal testing is a good baseline for every cat.

What if my cat keeps getting worms?

Reinfection usually means the source was not eliminated. Fleas, rodents, contaminated soil, or another untreated cat in the house are common culprits. Your vet can help you find the gap and close it.

References

Prevalence of intestinal parasites in owned and shelter cats in Slovakia and felines from Slovak Zoos: A three-year survey with special focus on Toxoplasma gondii. Current research in parasitology & vector-borne diseases, 2025.
Occurrence of Cystoisospora spp. and other intestinal parasites in dogs and cats with diarrhea. Veterinary parasitology, 2025.
Parasitic Worms of the Skin in Cats - Cat Owners. Merck Veterinary Manual.
Improving cestode diagnosis in domestic dogs and cats: the need for accurate and non-invasive techniques. Preventive veterinary medicine, 2025.
Antibody response after feline panleukopenia virus vaccination in kittens with and without intestinal parasites. Journal of feline medicine and surgery, 2024.
Parasites in Cats - Cat Owners. Merck Veterinary Manual.