How often should you really worm a cat?

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Intestinal worms are extremely common in cats, in fact one in four cats were found to have worms. The chances are that your cat will pick up these unpleasant parasites sooner or later.

The only way to be sure your cat is protected is to regularly worm at least four times a year (and much more for adventurous outdoor cats and keen hunters).

So, how often should you worm your cat? Let’s find out.

The benefits of worming

  • Keeping your cat healthy: Cats with worms may appear perfectly happy and healthy on the outside, but on the inside, it’s a different story. Worms live in the intestines and continue to feed on your cat’s precious nutrients or blood. In some cases, this can lead to weight loss, increased appetite, diarrhoea, dry and coarse-looking fur, and weakness. Severe infections can lead to anaemia or a ‘pot belly’.
  • Preventing reinfection: Most wormers work by paralysing and killing the worms in your cat. Therefore, regular, continuous worming is vital to remove any further worms that are picked up.
  • Protecting yourself and your loved ones: Some worms, like roundworms, can pass to humans where their larvae migrate through the body and can cause damage to organs and the eyes. Although this is very rare, it can be serious, especially for young children, leading to blindness in extreme cases.

So how often should I worm my cat?

  • Adult cats: Most cats should be wormed at least every three months – that’s four times a year, once for each season.
  • Prolific hunting cats: Cats that like to hunt are at much higher risk of getting worms from eating infected rodents like mice. For this reason, your vet is likely to recommend worming monthly.
  • Kittens: If you’ve just got a weaned kitten that’s never been wormed, or you don’t know if or when they were last wormed, it’s recommended that you treat them immediately. Then you should worm them every two weeks until they are eight weeks old. After this, it’s safe to worm every month until they are six months old and then decrease to once every one to three months (find out more in our article on worming kittens).
  • Pregnant and nursing cats: It’s recommended that these cats are wormed before mating, after the end of pregnancy and then during lactation with the kittens first worming treatment. Before worming, check with your vet which products are suitable for use on pregnant and lactating cats.
vet holding cat on a veterinary table

What kind of wormer should I use?

There are various types of worming treatments, which can be given to your cat in different ways, such as tablets or spot-ons. Your vet will be able to advise on the best type for your cat.

  • Tablets - Usually given to cats directly or mixed into their food, worming tablets are by far the most common type available.
  • Spot-on - Spot-on wormers are applied in the same way as some flea treatments by simply adding drops to the cat’s neck near the base of the skull.
  • Paste or granule - While some find this format harder to administer than tablets and drops, this is another option available to pet owners, especially those who like to mix worming treatments into their cat’s food.

Which types of intestinal worms do I need to treat for?

Roundworms and tapeworms are the most common types of worms your cat is likely to pick up. The chances of your cat contracting various other types of worms such as lungworm are much lower.

  • Roundworms - These occur in cats of all ages around the world. Cats may ingest roundworm eggs from a contaminated environment, by eating raw or undercooked meat, or become infected by eating rodents with a roundworm infection. Adult roundworms can reach up to four inches long and live in the cat’s intestine where they survive on food eaten by your cat.
  • Tapeworms - Long, flat and made of many segments, these worms are transmitted to cats via small rodents or fleas. They live in the small intestine and absorb nutrients eaten by your cat. Sometimes their segments can be spotted as they are passed in your cat’s faeces, appearing like grains of rice. Whereas roundworms are a problem for all cats, especially kittens, tapeworms are likely to affect older cats, unless a kitten has fleas.

Is it necessary to worm an indoor cat?

In short, yes. All cats should be regularly wormed. Tapeworm-carrying fleas can easily get into our homes, hitching a ride on our clothes and bags, other pets or visitors. Indoor cats can all too easily ingest fleas – along with tapeworms – when they’re grooming themselves, unwittingly infecting themselves with intestinal worms.

ginger cat lying on pet owners bed

Don’t forget about protecting your cat from fleas

Did you know a single cat flea can lay around 2,000 eggs in its lifetime?2 Come flea season in the warmer months, it doesn’t take long for one pest to quickly multiply into an infestation as the flea’s lifecycle – from egg to adult – can be as quick as 14 days in ideal conditions. As fleas carry worms, they bring with them double trouble for cats. Once a cat swallows a flea (often accidently when grooming) they can potentially develop a tapeworm infection.

Regularly treating your cat every month to prevent fleas can also help prevent them from contracting tapeworms.


1Wright et al, JSAP (2016) 57,393-5: 26% of cats were infected with T.cati.

2 Dryden MW, Host association, on-host longevity and egg production of Ctenocephalides felis felis. Veterinary Parasitology 34, 117–122 (1989).

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Date of review February 2022

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