worms in dogs and cats: types, signs, and prevention

Worms are common parasites that can affect dogs and cats. The main intestinal worms are roundworms, hookworms, tapeworms, and whipworms (mostly seen in dogs).

Heartworm is a different type of parasite that is spread by mosquitoes and lives in the heart and lungs.

Signs of intestinal worms can include visible worms or rice-like segments in stool, diarrhea, weight loss, a potbellied appearance, vomiting, or scooting. But many pets show few or no signs early in an infection.

The best way to find out whether your pet has worms is through the appropriate veterinary testing. Most intestinal worms are detected with a fecal test, while heartworm requires a blood test. Tapeworms are often identified from the segments an owner notices.

If you suspect your pet has worms, bring a fresh stool sample to your Banfield veterinary team when possible. Get a pet parasite check

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What types of worms do dogs and cats get?

Dogs and cats can get several different types of worms. Each has a different life cycle, route of infection, and potential health risk.

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Roundworms

Roundworms are long, pale worms that can look like strands of spaghetti in stool or vomit. They are especially common in puppies and kittens and can cause a potbellied appearance, poor growth, diarrhea, or vomiting. Learn more in our roundworm guide

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Hookworms

Hookworms are small intestinal worms that feed on blood and can cause anemia, especially in puppies and kittens. Most owners do not see the worms themselves, but dark, tarry stool, pale gums, weakness, and poor growth can be warning signs. Learn more in our hookworm guide

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Whipworms

Whipworms are intestinal worms found primarily in dogs. They can cause diarrhea, weight loss, and blood or mucus in the stool, although some infected dogs have no obvious signs. Learn more in our whipworm guide

Tapeworms

Tapeworms are flat intestinal worms. The sign owners most often notice is a small, white segment that looks like a grain of rice or sesame seed around the pet's tail, in stool, or on bedding. Fleas are a common source of tapeworm infection. Learn more in our tapeworm guide

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Heartworms

Heartworms are different from intestinal worms. They are spread by mosquitoes and live in the heart and lungs, where they can cause serious disease. Heartworm is prevented differently from intestinal worms and is typically screened for with a blood test. Learn more in our heartworm guide

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Ringworm

Ringworm is not actually a worm. It is a fungal infection of the skin that can cause hair loss and scaling and can spread between pets and people. If you are seeing a suspicious skin lesion rather than worms in stool, see our ringworm guide

Giardia and coccidia can also cause diarrhea in dogs and cats, but they are single-celled parasites rather than worms. Learn more in our guide to single-celled parasites

How can I tell if my pet has worms?

You may notice worms or rice-like segments in your pet's stool or around the tail. Other possible signs include diarrhea, vomiting, weight loss, a dull coat, a potbellied appearance in a young pet, or scooting.

Scooting can happen when a pet has tapeworm segments irritating the area around the anus, but it can also be caused by anal gland problems. Because of that, scooting is a reason to contact your veterinary team rather than assuming your pet has worms.

Many infected pets look completely healthy, especially early in an infection. Routine parasite testing can detect infections that are not obvious from your pet's appearance or behavior.

What do worms in poop look like?

Some worms are easier to recognize than others.

Roundworms: Pale, round, and spaghetti-like. They may be several inches long and can sometimes be seen in stool or vomit.
Tapeworm segments: Small, flat, and white or cream-colored. Fresh segments can look like grains of rice, while dried segments can resemble sesame seeds.
Hookworms: Usually too small to see in stool. A fecal test is used to look for their microscopic eggs.
Whipworms: Also generally too small to see with the naked eye and are usually identified through fecal testing.

Seeing nothing unusual in your pet's stool does not rule out worms. Many worm eggs are microscopic, and some parasites are not reliably detected from what you can see at home.

If you see something unusual, take a clear photo or save a small sample if you can do so safely. Your veterinary team can help determine whether it could be a parasite and whether testing is needed.

How do pets get worms?

Pets can pick up worms in several ways, depending on the parasite. If not passed from their mother, these are the most common:

swallow microscopic eggs from contaminated soil or stool
eat infected prey
swallow an infected flea while grooming
a mosquito bite (heartworm)

Transmission from mother to young differs by species. Puppies can pick up roundworms before birth and through their mother's milk, while kittens have no prenatal route and are infected mainly from the environment, prey, or, in limited cases, through nursing.

Shared ground at dog parks, daycare, boarding facilities, shelters, and other areas where many animals spend time can increase exposure to parasites. A pet does not have to roam outdoors to be exposed, either. Indoor cats can encounter fleas or rodents that enter the home, from parasite material tracked indoors, or be bitten by a mosquito that carries heartworm.

How does the vet test for worms?

A fecal test is the standard way to find most intestinal worms because it looks for microscopic eggs or other parasite material in stool. Heartworm is different and requires a blood test.

Tapeworms are an important exception. The common flea tapeworm is often missed on a routine fecal test, so telling your veterinary team about rice-like segments you have seen can be an important part of the diagnosis.

Worms may not shed eggs consistently, so one negative fecal test does not always rule out an infection. Your veterinary team may recommend repeat testing when your pet's signs or exposure history still suggest a parasite.

For a Banfield fecal-test visit, bring a fresh, same-day stool sample when possible. The veterinary team can examine the sample for common intestinal parasites and determine whether additional testing or another sample is needed.

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How are worms treated and prevented?

Worm treatment depends on the specific parasite. A veterinary team chooses a dewormer that targets the worm involved rather than relying on one product to treat every type of worm. Some infections require repeat doses and follow-up testing to confirm that the infection has cleared.

Year-round parasite prevention and routine fecal testing can help protect pets from common worms, but no single preventive covers every parasite. Your veterinary team can match prevention to your pet's species, age, lifestyle, and risk of exposure.

Flea control is also important for preventing flea tapeworms. If your pet has tapeworms, treating the worm without addressing an underlying flea problem can allow the infection to return. Learn more about how to get rid of fleas

Tip: Never use a dog parasite product on a cat unless your veterinarian specifically says it is safe. Some products intended for dogs can be toxic to cats.

Save on parasite treatment and prevention

Save on parasite treatment and prevention with Optimum Wellness Plans®. All plans include routine fecal testing and deworming, and select plans include a yearly heartworm test. You can also add parasite prevention to your pet’s plan at a discounted price. Explore OWPs

Can I get worms from my pet?

Some intestinal worms can infect people. Roundworms and hookworms can pose a risk to people, with young children at higher risk because they are more likely to put contaminated hands or soil in their mouths. Heartworm is not passed directly from pets to people.

Simple precautions help reduce exposure: wash your hands after handling pets or stool, clean up pet waste promptly, cover sandboxes, and wear shoes in areas where pets relieve themselves. If you develop symptoms that could be related to a parasite, contact your physician.

Worms FAQs

How do I collect a stool sample, and how fresh does it need to be?

Collect a small amount of fresh stool in a clean, sealed container and bring it to your veterinary team as soon as possible. The sample should be less than 24 hours old.

Can I drop off a sample without bringing my pet in?

Whether a stool sample can be dropped off without your pet depends on the circumstances and the vet’s recommendation. Contact your local Banfield hospital first to find out if they need to see your pet as well.

Do I need to treat my other pets at the same time?

It depends on the parasite and how it spreads. Because pets sharing a home or yard can share exposure, your veterinary team may recommend testing or preventive treatment for the other pets.

How long does a dewormer take to work?

The timing depends on the type of worm and the medication used. Some infections require more than one dose because the medication needs to be repeated after immature worms develop.

Is it normal to see worms in the stool after deworming?

It can be normal to see some worms or parasite material after treatment, depending on the type of worm and medication. Follow your veterinary team's instructions and let them know if you continue to see worms or your pet develops new or worsening signs.

Do I still need fecal tests if my pet is already on a monthly preventive?

Yes. Preventives can reduce the risk of some parasites but do not protect against every worm or eliminate the need for testing. Your veterinary team can recommend a fecal-testing schedule based on your pet's age and exposure risk.

Do over-the-counter or natural dewormers work?

Not all dewormers treat all types of worms, and products can differ in dosing and safety. Talk with your veterinary team before giving your pet an over-the-counter or natural dewormer so the treatment matches the parasite.

Do I need to clean my yard or litter box after a diagnosis?

Prompt stool cleanup helps reduce environmental contamination, while regular litter-box cleaning helps limit exposure in cats. Your veterinary team can give you specific cleaning recommendations based on the parasite involved.

How often should my pet be dewormed?

There is no single deworming schedule for every pet. Puppies and kittens often follow a specific deworming schedule, while adult pets need parasite prevention and fecal testing based on their individual risk.

When to contact your veterinary team

Reach out to your veterinarian if you see visible worms or segments, or if your pet develops diarrhea lasting more than a day or two, blood or mucus in the stool, weight loss, a potbellied appearance in a young pet, or repeated vomiting.

Coughing or tiring easily can point toward heartworm rather than an intestinal worm and should also be discussed with your veterinarian.

Very pale or white gums, collapse, severe weakness, or a limp young pet can indicate a serious problem and require the nearest emergency animal hospital right away. These signs should not wait for a routine parasite appointment. Learn more about pet first aid and emergencies

Book an exam or parasite screening with Banfield

If you think your pet may have worms, book an exam or parasite screening with your Banfield veterinary team. Bring a fresh stool sample when possible, and take a photo of anything unusual you have seen in your pet's stool or around their tail.

Find a Banfield near you

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Important Notice: The information provided on this page is for informational purposes only and is not a substitute for professional veterinary advice. Always consult a veterinarian with any questions regarding your pet's health or medical condition. Never disregard or delay seeking professional veterinary advice based on information from this page.