Should I Be Deworming My Cat? Experts Explain

“My cat is an indoor only cat, so I don’t need to treat them for worms, right?!” A sentence all vets have heard – but unfortunately, isn’t strictly true. All cats should have an anti-parasite treatment, but what and when varies according to a number of reasons. Read on to look into how you can protect your cat best for their individual situation. 

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Why do you need to worm-treat cats?

Cats can get worms just like dogs, and people(!), so we need to both prevent and treat them for worms throughout their lives. Cats act as either an intermediate host or as a final definitive host for the parasite. In this article we talk about “worming cats” as this is usually how it is termed, even though technically we mean “de-worming”: using anti-parasitic treatment called ‘anthelmintics’ to treat internal worms also known as ‘helminths’.

These worms are spread throughout the UK and Europe, and with climate change and the rise in movements of pets overseas the risk of contracting non-native parasites is increasing. 

How cats get infected with worms

The route of transmission is usually by your cat ingesting worm eggs or larvae from the environment, raw meat and fish, or ingesting fleas through grooming. Some spread through mosquito bites or even through kittens drinking their mother’s milk.

Signs your cat has worms

The signs that your cat has worms can be difficult to spot as they can be mild. A sparse or thinning coat or weight loss are sometimes apparent, whereas other signs can be a bit clearer such as a pot-bellied appearance or seeing the worms in their vomit or faeces. You may spot tapeworm segments which hold the eggs, these look like little grains of rice, on or around your cat’s anus or in their bed.

How often to worm cats

How often to worm your cat depends on age, routine and local risk of types of parasite. Being an outdoor cat that hunts rodents, or a pet who travels to other countries can increase the risk of getting worms. All kittens need worming as one type of worm lays dormant in the queen (the mum) and passes onto the kittens through her milk.

Recommended worming schedule for cats

Always talk to your vet about what would be best for your feline friend and what increased risks are in your area, but to help, the European Scientific Counsel on Companion Animal Parasites (ESCCAP) has written some guidelines. These guidelines suggest, for:

• Outdoor cats

Cats who go outdoors are at a higher risk for roundworms and tapeworms so treat or test faeces every 1–3 months.

• Indoor cats

Lower risk, but can still contract worms through biting insects and eggs brought in by others. They should be treated, or test faeces and treat accordingly 1–2 times per year.

• Kittens

Kittens should be treated for worms from three weeks of age then every two weeks until weaning, and then monthly until six months old.

• High-risk cats

Examples of increased risk scenarios include eating raw meat and fish, flea infestations as they are intermediate hosts to tapeworm, competition cats or those visiting catteries, and cats sharing a home with children under five or immunocompromised individuals. 

Common types of worms in cats

There are a variety of different worms that are found in cats, we can separate them into two categories; intestinal and non-intestinal worms.

Intestinal worms include roundworms, hookworms and tapeworms whereas non-intestinal worms include lungworms and worms more commonly found outside the UK such as heartworm and eye worms.

Types of worming treatments for cats

Worming treatments for cats can be found in tablet, granule or topical spot-on forms. 

How to choose the right worming treatment for cats

The most effective worming treatments are ones prescribed by your vets, ideally based on a faecal test to check which worms your cat needs treatment against. This reduces the amount of medication given to your cat over their lifetime and reduces the risk of anthelmintic resistance, which is when the worms become resistant to the medication.

Potential side effects of worming medications

Worming treatments prescribed by your vet are generally safe, however with any medication there can be rare side effects. These are usually mild symptoms such as vomiting, diarrhoea, drooling and reduced appetite. 

If any of these symptoms appear they should be mentioned to your vet as if feeling unwell it may be best in future to use a different medication which suits your pet more and symptomatic treatment will be available through your vets. More serious side effects are rarer still but can include neurological symptoms such as ataxia (wobbliness), if this is seen contact your vet as soon as possible.

How to prevent worm infestations in cats

Preventing worm infestations in cats is done through routinely giving worming treatment either prophylactically (preventative treatment) or as needed by testing their faeces to check which worming treatment they need. 

Other ways to reduce the risk include not feeding raw meat or fish, or if feeding raw make sure it has been frozen for one week at -17 to -20C. Always keep up good hygiene within the household with a pet, removing faeces from litter trays and the garden promptly, washing hands and grooming them regularly.

Bottom line: how often should you worm your cat

Speak to your vet for individual specifics, but generally adult cats should be wormed every 1–3 months if at higher risk (eg, outdoor cats, hunters) or at least 1–2 times a year if at low risk and kept indoors. 

Kittens should all be wormed from 2–3 weeks of age (depending on weight), then every two weeks until weaning then monthly until six months old.

Frequently asked questions

How should I clean my house if my cat has worms?

Good hygiene is key, clean and wash your cats bedding and areas where they sleep, hand washing after petting and grooming regularly to reduce transmission.

Can kittens be dewormed?

Yes, and they should be! They can be wormed from two weeks of age (depending on type of wormer and weight of kitten) so check with your vets which medication they and their mother need.

What happens if you don't treat worms in cats?

Worms can build up inside your cat if not treated appropriately. This can lead to internal blockages, weight loss, anaemia, lung damage and breathing problems, and even death in those young or vulnerable.

How do I know if my cat needs worming?

All cats need worming treatment, when and what for are dependent on age, local area risks along with individual risks. Ask your vet in order to get the best protection for your pet.

Resources

“ Guidelines | GL1: Worm Control in Dogs and Cats.” esccap.org.

Helm, Jenny, and Eric Morgan. “ Canine and Feline Lungworm Infections in the UK.” In Practice, vol. 39, no. 7, July 2017, pp. 298–315.

RCVS. “ ‘Under Care’ - New Guidance.” Professionals, 2023.