How Does Revolution Kill Roundworms in Cats?

Roundworms can pass through a mother's milk.
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Revolution is the first feline topical roundworm treatment approved by the U.S. Food and Drug Administration. Selamectin, its active ingredient, is responsible for its action against roundworms and other parasites. Keep your kitty safe from parasites by asking your veterinarian about appropriate worming products and schedules.


Roundworms are internal parasites. They're the most common intestinal worm to affect cats and dogs. Your kitty can acquire this unpleasant company from her mother's milk, by consuming infected animals, or by ingesting eggs in her environment.

Mild infections don't generally cause symptoms. But as infections worsen, your kitty is at risk for complications such as digestive discomfort, vomiting, weight loss, anemia, dull coat and a potbelly. Adult roundworms might be visible in your cat's stool or vomit. If you suspect a roundworm infection, head to the vet's office.


Revolution is the brand name of a clear to yellow topical antiparasitic agent for cats and dogs, manufactured by Pfizer. Its active ingredient is the chemical compound selamectin. This parasiticide treats and helps prevent infections by roundworms, fleas, ear mites, hookworms and heartworms. Revolution is approved for use in your kitty if she's at least 8 weeks old.

Killing Roundworms

The selamectin in Revolution is absorbed through your kitty's skin, and then it enters her bloodstream. From there, it is redistributed to your cat's skin, tissue, fat and organs.

When roundworms come into contact with selamectin, it interferes with their nerve impulses, paralyzing them. The roundworms no longer can adhere to your cat's intestinal walls, and they pass through the digestive tract and out with stool. The parasites quickly die without a host.

Using Revolution to Kill Roundworms

For Revolution to safely and effectively kill roundworms, it must be used properly. Apply it only with your vet's clearance, and as directed. Read the full label before use. Buy the color-coded package labeled for your kitty's body weight and apply one pre-dosed tube per month according to the manufacturer's instructions. A combination of tubes might be needed if you have a big cat. Your vet can demonstrate proper application.

Revolution is safe at recommended dosages in healthy cats 8 weeks or older and in pregnant, nursing and breeding cats. Side effects are rare, but they can include digestive upset or temporary hair loss at the site of application. If your kitty is sick, weak or underweight, don't use Revolution.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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