Roundworms in Cats: Signs, Prevention, and Treatment Options

Roundworms in cats are one of the most common intestinal parasites found in felines worldwide. These spaghetti-like worms can affect cats of any age, but kittens are especially vulnerable. Understanding how roundworm infections happen — and how to prevent them — is the first step toward keeping your cat healthy and parasite-free.

What Are Roundworms?

Roundworms (most commonly Toxocara cati and Toxascaris leonina) are intestinal parasites that live in a cat's digestive tract. Adult worms can grow up to 10 centimetres long, feeding on partially digested food in the gut.

Because they absorb nutrients meant for your cat, a heavy roundworm burden can lead to malnutrition — particularly in young kittens. These parasites are also zoonotic, meaning they can occasionally be transmitted to humans, which makes effective prevention even more important for the whole household.

How Cats Get Roundworms

Cats typically become infected by ingesting roundworm eggs from contaminated soil, water, or faeces. Outdoor cats that hunt are at higher risk because rodents and birds can carry roundworm larvae in their tissues.

Kittens are often infected before they are even born. Larvae can pass from a mother cat to her kittens through the placenta or through her milk during nursing. This is why kittens should begin a deworming schedule from a very young age.

Indoor cats are not immune either. Roundworm eggs can be tracked inside on shoes or clothing, and curious cats may encounter them through household insects that have come into contact with contaminated material.

Signs and Symptoms to Watch For

Many cats with a mild roundworm infection show no obvious symptoms at all, which is why routine prevention matters so much. When signs do appear, they tend to be more noticeable in kittens and cats with heavier worm burdens.

Common symptoms include:

• A pot-bellied appearance, especially in kittens
• Weight loss or failure to gain weight despite eating normally
• Dull, rough coat
• Vomiting — sometimes with visible worms
• Diarrhoea or changes in stool consistency
• Visible worms in faeces or vomit (they look like pale, coiled strands)
• Lethargy and general poor condition

If you notice any of these signs, it is important to act quickly. Left untreated, a severe infestation can cause intestinal blockages and serious health complications in young or immunocompromised cats.

How Roundworms in Cats Are Treated

Treating roundworms involves administering an appropriate cat worming product that targets intestinal parasites. These treatments work by either paralysing or dissolving the worms so they are passed naturally through the cat's digestive system.

Most worming treatments need to be repeated after a set interval — commonly two to four weeks — because they kill adult worms but may not destroy larvae or eggs that are still maturing. Following the product's recommended schedule ensures the full lifecycle of the parasite is addressed.

For kittens, deworming typically starts from around two weeks of age, with treatments repeated at regular intervals during the first few months of life. Adult cats benefit from ongoing, routine deworming as part of a broader parasite prevention plan.

Preventing Roundworm Infections

Prevention is far easier — and less stressful for your cat — than dealing with an active infestation. A consistent deworming routine is the single most effective step you can take.

Many modern cat flea and worming products combine protection against multiple parasites in a single treatment, making it simple to stay on top of your cat's prevention schedule. Look for broad-spectrum formulas that cover roundworms alongside other common intestinal worms.

Good hygiene also plays an important role. Clean litter trays daily, as roundworm eggs need one to three days outside the host to become infectious. Wash your hands after handling litter or soil, and discourage your cat from hunting if possible.

For multi-cat households, treat all cats at the same time to prevent reinfection. Keeping the indoor environment clean and vacuuming regularly can further reduce the risk of environmental contamination.

Frequently Asked Questions

Can indoor cats get roundworms?

Yes. While outdoor cats face a higher risk, indoor cats can still be exposed to roundworm eggs carried inside on shoes, clothing, or insects. Kittens may also be born with roundworms passed from their mother. Regular preventative treatment is recommended for all cats regardless of lifestyle.

How often should I deworm my cat for roundworms?

Most experts recommend deworming adult cats at least every three months as a baseline. Cats that hunt, live with other animals, or have access to the outdoors may benefit from more frequent treatment. Always follow the schedule recommended on the product you choose.

Can I catch roundworms from my cat?

Roundworm infections are zoonotic, so humans — particularly young children — can become infected if they accidentally ingest roundworm eggs from a contaminated environment. Practising good hand hygiene and keeping your cat's deworming schedule up to date significantly reduces this risk.

Keeping your cat protected from roundworms does not need to be complicated. Browse our range of veterinary-grade cat worming treatments to find the right product for your feline, and have a chat with your vet if you are unsure which option suits your cat's needs best.