Worms are one of the most common health problems veterinarians see in cats, and one of the easiest to miss. A cat can carry a heavy worm burden and still eat, purr, and play. By the time you notice obvious signs, the parasites have usually been present for a while. The good news: feline intestinal worms are very treatable once you know which ones you’re dealing with — and that’s the part most cat owners get wrong.
This guide walks through the worms that affect cats, how to recognize them, why deworming isn’t one-size-fits-all, and how to keep them from coming back.
The common worms that affect cats
Not all worms are the same parasite, and they don’t respond to the same medication. Here’s what’s actually living in (or near) your cat.
Roundworms are the most common feline intestinal parasite, especially in kittens. They look like spaghetti — pale, several inches long — and you may see them in vomit or stool. Kittens are frequently infected before or shortly after birth through their mother’s milk, which is why deworming starts so young. The Cornell Feline Health Center notes roundworms are widespread in cats of all ages.
Tapeworms show up as small, flat, rice-like segments stuck to the fur around the anus or moving in bedding. Here’s the key link: cats almost always get tapeworms by swallowing an infected flea while grooming. That means flea control is tapeworm control. If your cat keeps getting tapeworms, you have a flea problem to solve — see our guide on getting rid of fleas on cats. Hunting cats can also pick up tapeworms from eating infected rodents.
Hookworms are tiny blood-feeders that latch onto the intestinal wall. They’re less common in cats than in dogs but more dangerous per worm, because heavy infections can cause anemia — especially risky in kittens and small cats.
Whipworms are uncommon in cats (far more a dog problem) but occasionally turn up, usually causing intestinal irritation and diarrhea.
Heartworm is the outlier. It’s spread by mosquito bites, not swallowed, and the worms live in the lungs and heart — not the gut. This matters enormously: there is no safe, reliable cure for heartworm in cats. The drug used in dogs isn’t approved for cats and can be fatal. For cats, prevention is the entire game, and because mosquitoes get indoors, even strictly indoor cats need a heartworm preventive.
How cats catch worms
Worms reach cats through a handful of everyday routes:
- Nursing — kittens get roundworms through their mother’s milk.
- Hunting and eating prey — rodents and birds carry roundworm, tapeworm, and hookworm stages.
- Swallowing fleas — the standard path to tapeworms during grooming.
- Contaminated soil or feces — roundworm and hookworm eggs/larvae in the environment, including potting soil and shared litter boxes.
- Mother to kitten — the reason kittens are dewormed on a schedule regardless of symptoms.
This is also why indoor cats are still at risk. Fleas hitch rides on people and other pets, a single mouse can slip into a garage, eggs can be tracked in on shoes, and bagged potting soil isn’t sterile. Indoor living lowers exposure — it doesn’t eliminate it.
Symptoms to watch for
Many cats — particularly adults — show no early signs at all. When symptoms do appear, they range from the obvious to the easily-overlooked.
| Sign | What it can mean |
|---|---|
| Spaghetti-like worms in stool or vomit | Roundworms |
| Rice-like white segments near the anus or in bedding | Tapeworms |
| Vomiting (sometimes containing worms) | Roundworms; general parasite irritation |
| Diarrhea, sometimes with mucus or blood | Hookworms, whipworms, heavy roundworm load |
| Pot-bellied appearance, especially in kittens | Heavy roundworm burden |
| Dull, poor coat | Chronic parasite drain |
| Weight loss despite a good appetite | Worms competing for nutrients |
| Scooting or licking the rear | Tapeworm segment irritation |
| Pale gums, weakness, lethargy | Anemia — often hookworms |
| Failure to thrive / poor growth in kittens | Significant parasite load |
If your cat is vomiting, our guide on why cats vomit covers when it’s an emergency versus a passing upset. Persistent loose stool is worth reading up on too — see cat diarrhea causes and what to do. And if a new kitten isn’t gaining weight or growing as expected, parasites are a leading suspect; the new kitten checklist includes the early deworming and fecal-test steps most kittens need.
A note on people: worms and your family
Be aware without panicking. Some feline worms are zoonotic — meaning they can infect humans. Roundworm and hookworm larvae passed in cat feces can affect people, and the CDC notes children are at highest risk because they’re more likely to touch contaminated soil and put hands in their mouths.
The defense is ordinary hygiene, not getting rid of your cat:
- Wash hands after handling the litter box, soil, or your cat.
- Scoop the litter box daily — fresh eggs aren’t immediately infective, so promptness helps.
- Cover children’s sandboxes when not in use.
- Keep your cat on year-round prevention to reduce the eggs being shed.
Tapeworms rarely pass to humans and require actually swallowing an infected flea, so they’re a much smaller concern.
Treatment: don’t guess — test and treat
Here’s the single most important point. Different worms require different dewormers. A product that clears roundworms may do nothing for tapeworms; a tapeworm-specific drug won’t touch hookworms. Over-the-counter dewormers are a common trap — many skip tapeworms entirely, and getting the dose wrong is easy and risky in a small animal.
The reliable path:
- See your veterinarian and bring a fresh stool sample if you can.
- Fecal test — the vet checks the stool under a microscope to identify which worm (or worms) are present. Some worms shed eggs intermittently, so a follow-up test is sometimes needed.
- Targeted dewormer — your vet prescribes the right drug for the confirmed parasite, often as repeated doses spaced out to catch worms that were still maturing during the first treatment.
- Kittens follow a schedule — most are dewormed repeatedly starting at a few weeks of age, because roundworm infection is so common from the mother.
Never use a dog dewormer on a cat, and skip the home remedies. Some canine ingredients are toxic to cats, dosing differs by species and weight, and folk treatments like garlic or diatomaceous earth don’t reliably kill worms — they just delay real treatment while the infection continues.
Prevention that actually works
Once your cat is clear, keeping worms away is straightforward and overlaps neatly with flea and heartworm control:
- Year-round, vet-recommended parasite prevention. Many modern products cover several intestinal worms plus fleas and heartworm in a single monthly application. The CAPC recommends broad-spectrum, year-round prevention for cats.
- Stay on top of fleas — no fleas, far fewer tapeworms.
- Scoop the litter box daily and disinfect periodically.
- Limit hunting where you can; supervise outdoor time.
- Routine fecal checks at regular vet visits, even for healthy-looking cats.
When to call your vet
Schedule a visit if you see worms or rice-like segments, your cat has ongoing vomiting or diarrhea, a kitten looks pot-bellied or isn’t growing, or you notice pale gums and weakness (a possible sign of anemia that warrants prompt attention). For kittens, deworming and a first fecal test are routine, expected steps — not a sign something is wrong.
This guide is for general educational purposes and isn’t a substitute for individualized veterinary care. Worm identification and the correct dewormer depend on a fecal test, your cat’s age and weight, and your region. Always consult your veterinarian before starting any treatment or preventive.