Worms in cats

isolated cat


  • Worms are a common problem in pet cats and without regular treatment, most catch them at some point in their lives.
  • Worms are not often visible in poo until they have been treated and killed, making them difficult to spot.
  • Worming your cat every three months (or more regularly if they are an active hunter) will prevent problems from developing.
  • Worms live in the guts, eat your cat’s food and damage their gut lining. They don’t usually cause serious illness in adult cats (unless left untreated for a long time), but can cause serious illness in kittens.

Types of worms in cats

Two important types of gut worm affect pet cats in the UK:

  1. Roundworm look like spaghetti and grow up to 15cm long.
  2. Tapeworm grow up to 50cm long and look like flat ribbons made up of lots of little segments. If your cat has tapeworms, you might see the little segments (grain of rice size) crawling around their bottom.

Worms live in the intestines, eat your cat’s food and damage their gut lining. They cause weight loss, hunger and diarrhoea. Worms don’t often cause serious illness in adult cats (unless left untreated for a long time) but can cause serious illness in kittens.

How do cats get worms?

Most cats catch worms from eating worm-infected rats, mice or birds, or by eating fleas whilst grooming (fleas carry tapeworm).

Symptoms of worms in cats

Worms often cause symptoms such as:

Treating and preventing worms

Treating and preventing worms is simple, a worming tablet (or spot-on treatment) is all that’s needed. Most cats need a treatment every three months (more regularly if they are an active hunter). If your cat catches worms despite regular worming, you will need to talk to your vet about changing their worming regime.

Which cat worming tablet?

There are many different worming products available for cats (including tablets, liquids, pastes and spot-on treatments). Your vet will help you decide which is best for you and your cat, based on their lifestyle.

Always use a veterinary licenced product.

Products you can buy without a prescription (from a supermarket, human pharmacy, pet shop or online) are not veterinary licenced and often contain less effective ingredients.

It’s likely you’ll be able to buy a worming tablet from your vets, without an appointment if your cat has been examined in the past few months (and you know their weight). If your cat hasn’t been seen in over six months, is unwell or has lost/gained a lot of weight, they will need to be seen by your vet before having a worming tablet prescribed.

How to give your cat a tablet

Home remedies for worms in cats

To treat worms, you need to use a product with effective active ingredients. Home remedies and over the counter products are unlikely to work.

When to contact your vet

Book an appointment with your vet if you think your cat has worms. It may help to bring a sample of their poo (or a photograph) to show your vet. If your cat is healthy but hasn’t had a worming tablet for a while, contact your veterinary practice for advice.

Can humans catch cat worms?

It’s very rare for humans to catch cat worms, but it does occasionally happen. It’s most common in young children who have been playing in areas where cats have pooed. Cats worms cause damage to humans by lodging in organs such as the eyes, liver, heart and brain. If you have small children, it is extremely important to regularly worm your cat with an effective product.

Worms in kittens

Worms can cause serious illness in kittens. In large numbers, they can cause diarrhoea, bloating/pot-belly, poor coat condition, gut blockages, intussusceptions, anaemia and even death.

How do kittens get worms?

Kittens can catch worms from their mother’s milk, and once they start going outside, they can catch them in the same way that an adult cat can (from fleas, birds and rodents).

Worming kittens

A kitten’s first worming treatment should be when they are three weeks old, after that, they should be wormed every two weeks until they are 16 weeks old. After 16 weeks, they need worming as regularly as your vet suggests (likely to be every one-three months).

Symptoms of worms in kittens

  • Increased appetite without weight gain
  • Pot belly
  • Diarrhoea
  • Poor coat condition
  • Vomiting (sometimes containing worms)
  • Blood in poo.
Published: November 2019

PetWise Pet Health Hub – brought to you thanks to support from players of People’s Postcode Lottery 

Written by vets and vet nurses. This advice is for UK pets only.

Illustrations by Samantha Elmhurst