When you see a flea on your cat, most of the problem is elsewhere: 95% of cat fleas are in the home, as eggs, larvae and cocoons, in the carpets, the sofa and your cat's bedding. Hence the vets' rule: treat the cat, every pet in the household and the home, and keep going for two to three months. Here is how to be sure your cat has fleas, which treatment to choose, which ones are dangerous for cats, how to treat the home, and what the risks are for people.
Cat fleas: the essentials in brief
| The culprit | the cat flea, Ctenocephalides felis: it is also the one found on dogs |
|---|---|
| Where the fleas are | 5% on the animal, 95% in the home |
| The test | fine comb and damp paper: flea dirt turns red |
| Treating the cat | a flea product made for cats, chosen with the vet |
| Forbidden | dog products containing permethrin: they can kill a cat |
| Treating the home | vacuum everywhere, wash bedding at 60 °C, household spray |
| How long | 2 to 3 months to clear an infestation |
| People | they bite, mostly on the ankles, but do not settle on us |
| Kittens | risk of anemia: see the vet without delay |
Sources: International Cat Care, MSD Veterinary Manual, Cornell University, Anses (the French health safety agency), the SPA (France's animal protection society). Details are at the end of the article.
Contents
How do I know if my cat has fleas?
Fleas are hard to see: cats swallow many of them while grooming, explains the charity International Cat Care. And not all cats scratch, warns the SPA: an infestation can go unnoticed. The signs to look for:
- your cat scratches, licks or nibbles itself more than usual;
- small black specks in the coat or on its bedding: flea dirt;
- small brown insects darting through the fur, on the belly, the back or near the tail;
- bites on you, on the ankles and calves;
- in an allergic cat: scabs around the neck and at the base of the tail, and hair loss.
The comb and damp paper test
This is the method described by International Cat Care, the Cornell Feline Health Center and the SPA:
- Sit your cat on a cloth or a large sheet of white paper.
- Run a fine comb through its coat, concentrating on the neck and the base of the tail.
- Look at what falls: fleas, or small black specks.
- Put the specks on damp cotton wool or paper. If they dissolve and leave a red-brown mark, they are flea dirt: digested blood.
The result is enough: even if you do not see a single flea, flea dirt proves your cat has them.
Flea dirt, but no fleas?
That is common. Cats swallow fleas while licking themselves, and in a very allergic cat you sometimes find none, notes the MSD Veterinary Manual. The dirt stays, though: reddish-black, comma-shaped specks. Also check the places where your cat sleeps.
Where are fleas found on a cat?
Mostly where the cat cannot lick itself: the back of the neck and the base of the tail, says veterinary dermatologist William Miller of the Cornell Feline Health Center. The SPA adds the head, the base of the ears, the hindquarters and the inside of the thighs.
The flea life cycle: why 95% are in the home
The adult flea lives on the cat, but the rest of its life takes place in your home. The figures from the MSD Veterinary Manual:
- The adult starts laying eggs one to two days after its first blood meal: up to 50 eggs a day, about 2,000 in its lifetime.
- The eggs, white and tiny, slide off the coat and fall onto bedding, carpets and the floor. They hatch in 1 to 6 days.
- The larvae avoid light and burrow into carpet fibers and cracks between floorboards. They feed on debris and adult flea droppings for 5 to 11 days, sometimes two to three weeks.
- The cocoon: the flea is fully formed in one to two weeks, but it can wait there for weeks, even up to a year, until an animal or a person comes near.
The whole cycle can be completed in 12 to 14 days; most often it takes 3 to 8 weeks. Under ideal conditions, a single female can give rise to about 20,000 adult fleas in 60 days, Dr Miller calculates.
This explains the figure given by International Cat Care, the SPA and the British RSPCA: 95% of fleas are in the environment, not on the animal. Treating only the cat means dealing with 5% of the problem.
Are there fleas in winter?
Outdoors, fleas do not survive the cold: below 3 °C for several days, they die at every stage. But in a heated home with carpets or rugs, they develop all year round, points out the British charity Cats Protection. The peak season runs from spring to fall.
My cat never goes out: how did it get fleas?
Fleas come in without your cat. They arrive on your clothes or your visitors', with another pet, or they were already waiting in the carpets, Cats Protection explains. A dog that goes out (see our guide dog fleas), a visit to the vet or a stay at a cattery is enough. The SPA confirms it: indoor cats are affected too.
Are fleas dangerous for my cat?
Yes, beyond the itching.
- Flea allergy dermatitis: many cats are allergic to flea saliva. A single bite can be enough, according to the SPA. The cat scratches, licks and chews itself; small scabs appear on the back, neck and face, and hair falls out.
- Anemia: fleas feed on blood. In a heavily infested kitten, the loss can be fatal. Older or sick cats also need watching.
- Tapeworm: fleas carry the larva of a flatworm, Dipylidium caninum. Cats become infected by swallowing fleas while grooming. You can spot it by small white “grains of rice” in the stools. The SPA advises worming a few days after the flea treatment.
- Bacteria: fleas spread between cats the bacterium of cat scratch disease, Bartonella henselae, which can pass to humans.
My cat has fleas: which treatment?
Ask your vet: that is the advice of every source we read. The choice depends on your cat's age, weight and condition (kitten, pregnant or nursing cat) and on the other pets in the household. Products sold in supermarkets are often less effective, and some are not safe for cats, International Cat Care warns. We do not sell flea treatments.
| Form | What International Cat Care says |
|---|---|
| Spot-on | widely available; safety and effectiveness vary between products; never a dog product |
| Tablet | simple if your cat accepts tablets; a product licensed for cats and recommended by the vet |
| Collar | generally not very effective, may irritate the skin and cause injury without a safety release; some newer collars do better |
| Pump spray | possible; the product must be safe for a cat that grooms itself |
| Aerosol | not recommended: older products, and the hissing noise frightens cats |
| Powder | not recommended: only active while it stays on the coat |
Source: International Cat Care. The SPA also advises against supermarket flea collars.
Never use a dog product on a cat. Dog flea treatments containing permethrin cause tremors, convulsions and sometimes coma and death in cats, which cannot eliminate the compound. A few drops on the skin, or licked, can be enough. In 2024, Anses recorded 82 cases in France, 34 of them serious, and four deaths. In case of an accident: wash the cat with lukewarm water and soap or dish soap, and call a vet. If you treat your dog, keep it away from the cat until the product is dry.
How fast does the treatment work?
Not instantly. Many products do not repel fleas or kill them on the spot: a flea can live and feed on the cat for 6 to 24 hours before dying, the MSD Veterinary Manual explains. Still seeing a few fleas in the first days does not mean the product is not working.
My cat still has fleas despite the treatment
This is the most common question, and the answer lies in the life cycle. The fleas you see are new fleas, emerging from cocoons in the home: until the environment is dealt with, more keep coming. The useful checks:
- are all the pets in the household treated, each with a product for its species?
- is the home treated (see below)?
- is the product renewed as often as its instructions say? Most routine treatments are applied about once a month, says the SPA;
- have you allowed enough time? Clearing an infestation usually takes 2 to 3 months.
If nothing changes, go back to your vet.
The flea comb: useful, but not a treatment
A fine comb does three things: it checks for fleas, removes some of them, and takes out dead fleas during treatment. But it is no substitute for a proper treatment, the SPA points out. Cats Protection advises dipping the comb in a bowl of soapy water between strokes, to drown the fleas. Our flea combs come in sets of 4 or 6, with a large comb for the back and small ones for the head and legs.
Vinegar, lemon, essential oils, diatomaceous earth: natural remedies
None has been proven to work. So-called natural products (eucalyptus, neem, tea tree, citrus oils and so on) have not been through the evaluation required of a veterinary medicine, some are toxic to cats, and none comes close to the effectiveness of a licensed product, International Cat Care sums up. The SPA says the same of essential oils, which are toxic to cats, and of diatomaceous earth: abrasive, with dust that can affect the airways. Do not put any of them on your cat.
Fleas on a kitten: what to do?
Act fast. It does not take many fleas to make a kitten anemic, Dr Miller warns, and that anemia can kill. But a kitten is sometimes too young for certain flea products: give nothing without your vet's advice, who will choose a product suited to its age and weight.
While you wait for the appointment, a fine comb removes fleas without any product: comb gently, and dip the comb in soapy water between strokes. Also treat the mother and the other pets, and wash the bedding.
How do you get rid of cat fleas in the home?
- Vacuum everywhere, and often: floors, carpets, baseboards, cracks between floorboards, under furniture, the sofa, cushions, curtains. Vacuuming reduces the number of fleas without eliminating them all.
- Throw the bag away immediately, outside; with a bagless vacuum, empty and clean the container.
- Wash your cat's bedding, throws and your own bed linen: at 60 °C, the SPA advises. Heavily infested bedding should be thrown away.
- Treat the home with an insecticide spray designed for the purpose, after vacuuming: it targets eggs and larvae. Follow the instructions, keep the cat out of the room, and cover the fish tank: these products are highly toxic to fish. Some sprays contain permethrin: the cat must not come into contact with them.
- Repeat: cocoons are resistant to treatments. You often have to repeat, on the pets as well as in the home.
Foggers and flea bombs are generally less effective than a spray, because they do not reach every corner, according to International Cat Care. For a massive infestation, a pest control company can help: tell them you have a cat.
Baking soda? The SPA suggests sprinkling it on fabrics a few hours before vacuuming, to dry out the larvae. It is an extra, not a treatment.
Fleas in the bed
If your cat sleeps with you, your bed is part of its bedding: eggs fall there as they do elsewhere. Wash sheets, covers and the comforter at 60 °C, vacuum the mattress and the bed base, and keep the cat out of the bedroom until things are back to normal, the SPA recommends.
How long does it take to get rid of them?
Allow 2 to 3 months, according to the MSD Veterinary Manual. It is not a failure of the treatment: it is the time the cocoons already present need to hatch. A flea that has left its cocoon survives only one to two weeks without a host, but it can stay inside that cocoon for months.
Do cat fleas bite humans?
Yes, they bite, but they do not settle on us. It is the newly emerged, unfed fleas that bite people, the MSD Veterinary Manual explains. The bites are mostly on the feet, ankles and calves. They do not stay: they feed on the cat's blood, not ours, says Cats Protection, which answers no to the question “can humans get fleas?”.
Two precautions all the same. The bites itch, sometimes a lot in sensitive people: if they bother you, ask your pharmacist or doctor. And fleas keep the bacterium of cat scratch disease circulating between cats, from which it can then reach humans: one more reason to treat.
The solution is not to treat yourself, but to treat the cat and the home.
Keeping fleas from coming back
- A regular treatment, chosen with your vet, is better than an infestation to clear up. Fleas survive all year round indoors, the SPA points out.
- Including for an indoor cat, Cats Protection insists.
- Every pet in the household, at the same time, each with its own product.
- A regular combing: the simplest way to spot fleas early.
- Vacuuming and washing bedding, in the places where your cat sleeps.
- Worming, since fleas transmit tapeworm: talk to your vet.
Cat fleas: our picks
We do not sell spot-ons, tablets or insecticide sprays: for those, see your vet. What we do have: what you need to spot fleas, look after the coat, and bedding that can be washed.
Flea combs, set of 4 or 6View product
Tick removerView product
Wood and steel combView product
Self-cleaning brushView product
Foldable, washable cat houseView product
Self-heating mat, washable coverView product
Frequently asked questions about cat fleas
How do I know if my cat has fleas?
Run a fine comb through its coat over a white cloth. Black specks that leave a red mark on damp paper are flea dirt: your cat has fleas.
How do you get rid of fleas on a cat fast?
With a flea product made for cats and recommended by your vet. The fleas on the cat die within about 6 to 24 hours, but you also need to treat the home, where 95% of the fleas are.
How do you get rid of cat fleas in the home?
Vacuum everywhere and throw the bag away, wash linen and bedding at 60 °C, then use a household spray. Treat every pet and repeat for 2 to 3 months.
My cat still has fleas after a spot-on: why?
The fleas you see are emerging from cocoons left in the home. Until the home and every pet are treated, new fleas keep coming. Allow 2 to 3 months.
My cat never goes out: can it have fleas?
Yes. Fleas come in on your clothes, with another pet or a visitor, and develop all year round in a heated home.
Can I catch my cat's fleas?
They can bite you, mostly on the ankles, but they do not settle on humans: they feed on the cat's blood.
Are cat fleas dangerous for humans?
Their bites itch, sometimes badly in sensitive people. Fleas also keep the bacterium of cat scratch disease circulating between cats.
Can you use a dog flea treatment on a cat?
Never. Dog products containing permethrin can kill a cat. In case of an accident, wash the cat with lukewarm soapy water and call a vet.
Do flea combs work?
For spotting fleas and removing some of them, yes. A comb does not treat an infestation: it complements the flea treatment, it does not replace it.
What natural remedy works against cat fleas?
None has been proven to work. Essential oils are toxic to cats, and diatomaceous earth irritates their airways.
Does vinegar kill cat fleas?
None of the veterinary sources we read recommends it: home remedies come nowhere near the effectiveness of a licensed flea product.
What should I do if my kitten has fleas?
See the vet quickly: fleas can make a kitten anemic. Give no product without the vet's advice; in the meantime, remove fleas with a fine comb.
How long does a cat flea live?
Its full life cycle usually lasts 3 to 8 weeks, but a flea can wait in its cocoon for months, sometimes up to a year.
How many eggs does a flea lay?
Up to 50 a day, and about 2,000 in its lifetime. The eggs fall off the coat and hatch in the home in 1 to 6 days.
Are there fleas in winter?
Outdoors, the cold kills them. In a heated home, they develop all year round.
Are cat fleas and dog fleas the same?
Most often, yes: most of the fleas found on both dogs and cats are cat fleas, Ctenocephalides felis.
My cat has fleas and sleeps on my bed: what should I do?
Treat the cat and the home, wash your bed linen at 60 °C, vacuum the mattress, and keep the cat out of the bedroom until the infestation is cleared.
Should you worm a cat that has fleas?
Yes: fleas carry a tapeworm that cats catch by swallowing them. The SPA advises worming a few days after the flea treatment.
Sources
- International Cat Care, fleas and flea control in cats
- MSD Veterinary Manual, fleas of cats, by Michael Dryden, Kansas State University
- Cornell Feline Health Center, fleas
- Anses, do not treat your cat with a dog flea product and use a product suited to your pet (in French)
- The SPA, cat fleas: everything you need to know (in French)
- Cats Protection, fleas
- RSPCA, how to get rid of fleas
- ASPCA, fleas and ticks
Article updated on October 4, 2026. This article is not a substitute for a consultation: the choice of a flea treatment is up to your vet. The photos in this article were generated by AI. Read also: dog ticks (the removal technique also works for cats), cat vomiting and cat age in human years.
