Grey Worms in Cat Box

A worm infestation in your kitty can show up in his box.

A worm infestation in your kitty can show up in his box.

It sounds gross. Your kitty has worms in his stool and you’ve spotted them in his litter box. Go ahead and let that shiver loose. It’s OK, because intestinal worms can either cause no symptoms in your cat -- or he may develop symptoms that truly worry you.

Health Implications of Worms

The implications of worms for your kitty’s health differ. He may not show any visible symptoms related to the intestinal infestation, or he may have several symptoms that your vet should check out. If your cat is showing some symptoms, but you’re just not sure, keep in mind the symptoms of parasitic infestation aren’t always specific. These symptoms can include a potbellied or bloated appearance, diarrhea, vomiting, coughing, constipation, weight loss or visible worms -- or segments of worms -- in his stool or clustered around his anus. His hair may be dull, not shining with health. Cats allowed to roam outdoors or cats who are exposed to areas that other animals use as their bathroom are more likely to suffer from an intestinal worm infestation. If you see worms in his feces or sticking to his anus, take him to the vet for diagnosis and possible treatment.


Tapeworms, also called cestodes, have a long, flat appearance. Think of a length of ribbon. This parasite is segmented. That is, this worm breaks apart into segments, with each segment filled with eggs. Adult tapeworms live in the small intestine of your cat. Once they arrive at this part of your cat’s digestive system, they embed their heads in the mucous membrane of the small intestine. The segments farthest from the worm’s head mature the soonest. Your kitty may lose weight or vomit after he develops a tapeworm infestation. Once they have matured, they break off, to be passed out of your cat’s body in his feces. You’ll be able to see segments about 1/4 inch long in your kitty’s poop and in his litter box. If you see these, grab your cat and look at his bottom -- you may be able to spot small worm segments near his tail, right by his anus. “Fresh” tapeworm segments look like rice grains. Older segments look like sesame seeds. He got this infestation by eating infected rodents or by swallowing infected fleas when he groomed himself. Prompt treatment is necessary, because tapeworms can be passed to humans.


Roundworms are the most common parasitic infestation in cats, according to the ASPCA. Your kitty can become infected with this parasite by eating their eggs or rodents infected with the larvae. Kittens develop this infestation when they drink breast milk from an infected queen cat -- the queen can pass it in her breast milk. Infection with this parasite can become life-threatening if the quantity of worms inside your cat’s intestines is so high that he suffers an intestinal blockage. This is the most dangerous to kittens if they are not treated for their infestation. Your vet can diagnose a roundworm infestation by completing a microscopic inspection of your cat’s feces. This parasite is about 3 to 4 inches long and looks a little bit like spaghetti. Treatment includes medication, reducing your cat’s ability to roam and treating queen cats before they begin breeding.

Treatment for Intestinal Worms

Now that you have been grossed out, think about treatment. Your vet will prescribe one of several medications for your cat to get rid of the infestation of worms in his intestines. Follow the dosing instructions and make sure your cat finishes the full prescription. Prevent reinfection by not allowing your cat to roam, avoiding raw meats, controlling rodents, ticks and fleas, and regularly washing his litter box with a disinfectant like diluted bleach.

About the Author

Genevieve Van Wyden began writing in 2007. She has written for “Tu Revista Latina” and owns three blogs. She has worked as a CPS social worker, gaining experience in the mental-health system. Van Wyden earned her Bachelor of Arts in journalism from New Mexico State University in 2006.

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