Worms in cats

isolated cat


  • Intestinal worms are a common problem in cats and kittens, without regular treatment most will catch them at some point in their life.
  • Worms steal food and cause damage to the gut lining, it’s rare for them to cause serious illness in adult cats but common for them to cause problems in kittens.
  • Regular deworming will prevent problems from developing.

General information

Worms live in the intestines, steal food and cause damage to the gut lining. Although worms rarely cause serious problems in adult cats, they can cause very serious illness (such as dehydration, anaemia, gut blockages and even death) in kittens.

Kittens catch worms from their mother’s milk and adult cats catch them from fleas and hunting (rats, mice and birds). There are two main types of worm that affect cats and kittens 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 little worm segments (the size of a grain of rice) crawling around their bottom.

Symptoms of worms in cats

Worms can cause symptoms such as:

Treating and preventing worms

Kittens. Your kitten will need a special worming treatment suited to their age and weight. They should have their first treatment at 3 weeks old and after that, they should be wormed every two weeks until they are 16 weeks old. After 16 weeks, they will need a treatment every one-three months (or as regularly as your vet suggests).

Adult cats. A worming treatment every three months is usually enough to prevent problems from developing. More regular treatments may be necessary if your cat hunts a lot.

What to expect after treatment. You probably won’t notice any changes after giving your cat a worming treatment, unless they had lots of worms, in which case you may see some dead worms in their poo. Contact your vet if your cat has diarrhoea or seems unwell.

Which wormer?

There are many different worming products available for cats (including tablets, liquids, pastes and spot-on treatments). The best one for your cat will depend on their temperament and lifestyle.

Prescription wormers. It’s best, wherever possible, to use a prescription worming treatment from your vet. If your cat is healthy and visits the vet regularly, your surgery is likely to be happy to dispense a worming treatment without an appointment. Your vet surgery will need to know how much your cat weighs so they can provide the right treatment dose. If your cat hasn't been examined for a while or you’ve tried a worming treatment from a pet shop or supermarket and it hasn’t worked, it’s best to book an appointment.

Non-prescription wormers. There are some worming treatments that are available without prescription, some are called ‘NFA-VPS’ products, meaning they can only be dispensed by a vet, pharmacist or ‘Qualified Person’ and are stored in a locked cupboard. These NFA-VPS products tend to be more effective than products that you can pick up from a shelf without speaking to someone. If you buy a NFA-VPS product, it's likely that you will be asked your cat's weight.

Home remedies for worms in cats

To treat worms, you need to use a product with proven ingredients. Unfortunately, home remedies are very unlikely to work.

How to give your cat a tablet

When to contact your vet

Contact 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 and needs a worming tablet, call your veterinary practice.

Can humans catch worms?

It’s very rare for humans to catch worms from a cat, but it does occasionally happen. It’s most common in young children who have been playing in areas where cats have toileted. Cat’s worms can cause illness in humans by lodging in organs such as the eyes, liver, heart and brain. If you have concerns for you or someone else, it is best to contact your doctor, or the NHS for advice. If you have small children, it is very important to deworm your cat regularly.

Published: June 2020

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

Illustrations by Samantha Elmhurst