Even house cats can get fleas and worms. Find out the best way to treat them 

Think your indoor cat is safe from fleas and worms? Think again. Even house cats can pick up these pesky parasites, sometimes in surprising ways. Cat welfare expert Emma Lane reveals how to protect house cats, even if they don’t go outdoors. 

Do indoor cats get fleas and worms? 

Indoor cats can still get fleas and worms even if they don’t go outside. 

Fleas

Fleas are tiny parasites that bite your cat and cause them to itch. The most common ways for cats to get fleas are:

• through coming into contact with another cat who has fleas
• from rodents they chase and catch outdoors

But even if your cat doesn’t usually leave the house, they can still catch fleas in several different ways. For example:

• fleas can get into your home on the clothes and bags of other cat owners who are visiting 
• fleas can get into your home on your own clothes and bags if you have visited a cat-owning friend 
• your cat can catch fleas from places like catteries or the vet and bring them home

Worms

Two types of intestinal worms are common in cats: tapeworm and roundworm. The most common way cats get worms is from eating prey such as birds or mice. But even if your cat doesn’t go outside and hunt, they could still get worms from:

• having fleas which carry worm larvae
• their mother's milk when they were a kitten 

Signs your indoor cat has fleas

• Scratching themselves more than usual
• Flea bites on their skin
• ‘Flea dirt’. This is dark flea droppings that you might see if you comb your cat with a fine-tooth comb
• Flea bites on you

If your cat has a flea allergy, you may also notice:

• hair loss due to excessive scratching and licking
• inflamed skin
• small scabs, especially around their neck and the base of their tail

If you notice any of these signs, get your cat checked by your vet. 

Signs your indoor cat has worms

• Tapeworm segments in your cat’s poo, around their bottom or in their bedding. These look like grains of rice
• Weight loss
• Eating more
• Itchy bottom
• Diarrhoea
• Kittens with a severe infestation can get a rounded potbelly

If you notice any of these signs, get your cat checked by your vet. 

Should I treat my house cat for fleas and worms?

Even if you’re not planning to let your cat outdoors, they could still get fleas or worms. Although their risk of getting fleas or worms may be lower than if they were an outdoor cat, it’s still a good idea to give them some protection. If your indoor cat were to get fleas or worms, it could make them very unwell. 

Speak to your vet about the best treatment for your cat and their situation. They will be able to tell you which is the best flea and worm medicine for your cat. 

If your indoor cat already has fleas or worms, you will need to treat your home as well as your cat. Flea and worm eggs can live in your carpets and other soft furnishings for months. They could then reinfect your cat if they come into contact with them. 

Speak to your vet about the best way to treat your home for fleas and worms. 

How often should I treat my indoor cats for fleas and worms?

Speak to your vet to find out how often you should treat your house cat for fleas and worms. The recommended frequency of parasite treatments depends on a cat’s lifestyle and health. If your cat doesn’t go outside, they may need treatment less frequently than an outdoor cat. 

How does cat flea and worm treatment work?

Cat flea and worm treatments usually come in the form of:

• tablets or pills
• injections
• spot-on treatment applied to the skin

The treatment contains ingredients that kill any fleas on your cat’s skin and worms in their digestive system. This disrupts the life cycle of the fleas and worms so they cannot reproduce. 

Can you get flea and worm treatment together for cats?

There are combined flea and worm treatments available for cats. These treat your cat for fleas and worms at the same time, so you don’t need to give them two different medications. Speak to your vet, who can tell you which is the best combined flea and worm treatment for your cat and their situation.

Find out more about fleas in cats and worms in cats.

Our partnership with Zoetis: Protecting cats, together 

Cats Protection is proud to officially partner with Zoetis from August 2025, following over 12 years of valued support. Zoetis supplies us with trusted flea and worming treatments that can even be used for kittens and nursing mums. These treatments are essential for ensuring every cat in our care is protected from parasites before they’re rehomed. 

Thanks to this long-standing relationship, we’ve already helped over 450,000 cats live healthier, happier lives. This partnership strengthens our ability to give every cat the best possible start in their new home.