Parasites in Cat Poop: Types, Signs, and Treatment

Name: Parasites in Cat Poop: Types, Signs, and Treatment
Creator: Dr. Zubair Khalid

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

Parasites in cat poop are common, and they range from spaghetti-like roundworms to microscopic protozoa you can only find with a lab test. Some cause diarrhea and weight loss, while others cause no signs at all. Because a few of these parasites can spread to people, knowing what to look for and when to call your vet matters for your whole household.

This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

Worms you can see in stool are usually roundworms (cream-colored, 3 to 5 inches long) or tapeworm segments (small, rice-like pieces) [1].
The most common parasites found on fecal tests in U.S. cats are Giardia, roundworms (Toxocara cati), and Cystoisospora (coccidia) [2].
Diarrhea is the most frequent sign, but many infected cats show no signs at all [3][1].
A single fecal sample can miss an infection, so your vet may recommend testing more than once or using several test methods [2].
Some cat parasites, including Toxocara and Toxoplasma gondii, can infect people, so prompt treatment and litter box hygiene protect your family [4][5].

What "Cat Poop Parasites" Actually Means

When owners talk about a cat poop parasite, they usually mean an internal parasite living somewhere in the digestive tract. These fall into two broad groups. The first is worms, which are multicellular and sometimes visible to the naked eye. The second is protozoa, single-celled organisms that are far too small to see without a microscope [1].

Common intestinal worms in cats include roundworms, hookworms, and tapeworms [4]. Common protozoa include Giardia, Cystoisospora (often called coccidia), and Cryptosporidium [2]. Toxoplasma gondii is another protozoan that can pass into cat droppings and has public health importance [4].

Not every parasite in the gut shows up in every bowel movement. Worms shed eggs and segments intermittently, and protozoa are shed in waves. That is why a normal-looking stool does not rule out an infection, and why a single negative test does not always close the case.

Signs Owners Notice

Gastrointestinal parasites often cause vague, nonspecific symptoms instead of one obvious clue. According to Cornell University's College of Veterinary Medicine, signs can include a dull coat, coughing, vomiting, diarrhea, mucousy or bloody feces, loss of appetite, pale mucous membranes, or a potbellied appearance [1]. The vomiting, diarrhea, anemia, and dehydration parasites cause can weaken a cat and make it more vulnerable to viral and bacterial infections [1].

What you might see in the litter box

Diarrhea, which may be soft, watery, or bloody. In one study of young cats with diarrhea, watery or hemorrhagic diarrhea was seen in some cats infected with Cystoisospora felis and Cystoisospora rivolta [6].
Worms or worm segments in the stool or stuck to the fur around the rear end. Roundworms may also be vomited [3].
Mucus coating the stool.
Stool that looks normal despite an active infection. Many cats with roundworms show no signs at all [3].

What you might see in your cat

Weight loss or poor growth, especially in kittens [3].
A swollen, distended belly, sometimes described as potbellied [3][1].
A dull, rough coat [3][1].
Scooting, licking, or irritation around the anus.
Low energy or reduced appetite.

If your cat has diarrhea along with visible worms, our guide to cat diarrhea with worms walks through the likely causes and what treatment usually involves.

Causes and Risk Factors

Cats pick up intestinal parasites in a few main ways. They can eat parasite eggs passed in the droppings of infected animals, or they can eat infected prey such as mice that carry the parasites [3]. Kittens can also get roundworms through the mother's milk, and adult worms can be found in the small intestine of kittens as early as 3 to 4 weeks of age [3].

Here is how the common parasites compare.

Parasite	How cats get it	What owners may see	Zoonotic (spreads to people)?
Roundworms (Toxocara cati, Toxascaris leonina)	Eggs in feces, infected prey, mother's milk [3]	Often none, or diarrhea, poor growth, potbelly, worms in stool or vomit [3][1]	Yes [4][5]
Hookworms	Contact with contaminated soil or stool	Diarrhea, weight loss, anemia	Yes
Tapeworms	Eating infected fleas or prey	Rice-like segments in stool or near the rear	Rarely
Giardia	Contaminated water, food, or surfaces	Diarrhea, sometimes intermittent	Yes [5][7]
Cystoisospora (coccidia)	Ingesting oocysts from the environment	Diarrhea, which can be watery or bloody [6]	No
Toxoplasma gondii	Infected prey, contaminated soil	Often none	Yes [4]

Risk factors that raise the odds of infection include being a kitten, going outdoors, hunting or eating prey, living in a multi-cat household, and coming from a shelter or a free-roaming background. In a study of free-roaming cats in New York City, 57.5% were infected with at least one parasite species, with Toxocara most common at 54%, followed by Ancylostoma (hookworms) at 13.8% and coccidia at 11.5% [8]. Those numbers are much higher than what you would expect in a well-cared-for indoor cat, but they show how much exposure outdoor access creates.

Cats with weakened immune systems, young kittens, and senior cats tend to have more severe signs. Pregnancy can also suppress a cat's natural resistance to roundworms, which is why mother cats may shed large numbers of eggs around the time they give birth [3].

How Veterinarians Diagnose Intestinal Parasites

Diagnosis starts with a fecal examination. Your vet will ask about your cat's history, including outdoor access, diet, and any recent diarrhea, then collect a fresh stool sample. Several testing methods may be used together because no single test catches everything.

Fecal flotation separates parasite eggs and oocysts from the stool so they can be seen under a microscope. This is the standard first-line test for worms and coccidia.
Coproantigen testing uses an enzyme-linked immunosorbent assay to detect parasite proteins in stool. It is especially useful for Giardia and Cryptosporidium, which can be hard to find on flotation alone.
Direct fluorescent antibody testing uses a stain and special microscope to detect protozoa such as Giardia and Cryptosporidium.
Baermann examination is used when lungworms or Strongyloides are suspected.

A large U.S. laboratory review of 15,395 feline fecal examinations in 2023 used centrifugal fecal flotation, coproantigen ELISA, direct fluorescent antibody testing, and Baermann examination together. Of those samples, 13.52% were positive for at least one parasite and 2.10% contained multiple types [2]. The most frequently detected parasite was Giardia at 4.82%, followed by Toxocara cati at 4.75% and Cystoisospora at 3.40% [2].

Because shedding is intermittent, your vet may ask you to bring in a second or third sample over several days. A negative result on one sample does not always mean your cat is parasite-free.

Treatment Options

Treatment depends on which parasite is found. Your veterinarian will choose a dewormer or antiprotozoal medication based on the specific organism, your cat's weight, age, and overall health. Doses are calculated by your vet from your cat's weight and health status, so never use an over-the-counter product or a dose meant for another animal without veterinary guidance.

For worms, common treatments include oral dewormers, topical products, and injectable medications. Many of these are also available as monthly broad-spectrum preventives that cover multiple parasites at once. For protozoa such as Giardia and Cystoisospora, treatment may involve a specific antiprotozoal drug plus supportive care for diarrhea and dehydration.

Kittens often need repeated deworming because they can be reinfected through the mother's milk and because their immune systems are still developing [3]. Adult cats with a heavy roundworm burden may also need more than one treatment to clear the infection.

If your cat has other skin or ear problems alongside the intestinal issue, our articles on ringworm on a cat's ear and cat skin infections cover those topics separately.

What about "cat poop fungus"?

Owners sometimes search for cat poop fungus because they see white, fuzzy, or stringy material in the litter box. True fungal infections of the intestinal tract are uncommon in cats. What people usually find is one of three things: tapeworm segments that look like grains of rice, roundworms that look like thin white noodles, or undigested material such as hair or plant fiber. If you are not sure what you are seeing, take a photo and bring a fresh sample to your vet. Do not assume it is fungus and treat it at home.

Recovery, Outlook, and Long-Term Management

Most cats recover well from intestinal parasites once the correct treatment is started. Diarrhea usually improves within a few days, though full resolution can take longer if the gut lining needs time to heal. Kittens and cats with heavy infections may need follow-up fecal tests to confirm the parasites are gone.

Long-term management centers on prevention and monitoring. The Merck Veterinary Manual recommends checking your cat's droppings and having them tested for worms once a year or more, especially if you have kittens or outdoor cats that may be exposed when they go outside [4]. Cats with ongoing diarrhea or repeated infections may need more frequent testing.

If your cat has a chronic or recurring problem, your vet may recommend a prescription preventive that covers the parasites your cat is most likely to encounter. Keeping your cat indoors, controlling fleas, and preventing hunting all reduce exposure.

Prevention

Prevention is easier than treatment, and it protects both your cat and your household.

Use year-round parasite prevention as recommended by your veterinarian [4].
Scoop the litter box daily. Fresh feces are less likely to release infective stages into the environment.
Wash your hands after cleaning the litter box or gardening.
Keep cats indoors or supervise outdoor time to reduce exposure to prey and contaminated soil.
Control fleas, since tapeworms are spread by eating infected fleas.
Test new cats and kittens before introducing them to other pets.
Avoid feeding raw or undercooked meat, which can carry Toxoplasma and other parasites.

Some cat parasites can cause disease in people. The parasite that causes toxoplasmosis can pass into cat droppings, and people can be exposed when they clean an infected cat's litter box [4]. Pregnant women, young children, and anyone with a weakened immune system (such as people with HIV or those receiving chemotherapy) are at higher risk [4]. If someone in your home falls into one of those groups, talk to your veterinarian about extra precautions.

For a broader look at parasites that affect both dogs and cats, see our guide to intestinal parasites in dogs and cats.

Limitations and When to Contact a Veterinarian

No article can tell you which parasite your cat has or how to treat it. That requires a fecal test and a veterinarian who can examine your cat. Individual cases need a veterinarian's assessment.

Call your veterinarian the same day if your cat has:

Bloody diarrhea or black, tarry stool
Vomiting that continues for more than 24 hours
Refusing to eat or drink
Visible worms in stool or vomit along with any of the above

Go to an emergency clinic now if your cat has:

Severe weakness, collapse, or difficulty breathing
A swollen, painful abdomen
Pale gums or a very fast heart rate
Diarrhea with signs of severe dehydration (tacky gums, skin that does not spring back)

Schedule a routine visit if you see:

Soft stool lasting more than two or three days
Rice-like segments around the rear end
Weight loss or a potbellied appearance
Any new cat or kitten that has not had a fecal test

Frequently Asked Questions

Can I get parasites from my cat's poop?

Yes, some cat intestinal parasites can infect people. Toxocara, Giardia, and Toxoplasma gondii are among the zoonotic parasites of concern [4][5]. Good litter box hygiene and hand washing greatly reduce the risk.

Can a cat have parasites with normal poop?

Yes. Many cats with roundworms show no signs at all, and normal-looking stool does not rule out an infection [3]. This is one reason annual fecal testing is recommended even for cats that seem healthy [4].

How long does deworming take to work?

Most dewormers start working within a day or two, but full clearance depends on the parasite and whether reinfection occurs. Kittens often need repeated treatments because they can be reinfected through the mother's milk [3]. Your vet will tell you when to bring in a follow-up sample.

Do indoor cats need parasite prevention?

Indoor cats have lower risk, but they are not risk-free. Fleas can carry tapeworms, and people can track parasite eggs indoors on shoes. Talk to your vet about a prevention plan that matches your cat's lifestyle.

What should I bring to the vet visit?

Bring a fresh stool sample, ideally less than 12 hours old, in a clean container or plastic bag. A photo of anything unusual you saw in the litter box also helps. If your cat has had diarrhea, note how long it has lasted and whether you have seen blood or mucus.

References

Gastrointestinal Parasites of Cats. Cornell University College of Veterinary Medicine.
Prevalence and epidemiologic patterns of feline parasitism detected by fecal examination in the United States, 2023. Veterinary parasitology, 2026.
Gastrointestinal Parasites of Cats - Cat Owners. Merck Veterinary Manual.
Parasites in Cats - Cat Owners. Merck Veterinary Manual.
Prevalence, risk factors, and zoonotic implications of gastrointestinal parasites in urban cats in Kazakhstan: A cross-sectional multicity study. Veterinary world, 2025.
Occurrence of Cystoisospora spp. and other intestinal parasites in dogs and cats with diarrhea. Veterinary parasitology, 2025.
Molecular detection and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in cats and dogs from metropolitan areas of Bangladesh. Food and waterborne parasitology, 2026.
Zoonotic endoparasites and Toxoplasma gondii seropositivity in free-roaming cats (Felis catus) from New York City boroughs. PloS one, 2026.