Frontline for cats: Plus, Spot On and Spray explained
Frontline for cats is one of the best-known flea treatments in the UK. It contains fipronil, which kills fleas, ticks and lice, and Frontline Plus adds an ingredient that stops flea eggs hatching. Here is how each version works, how to apply it properly, and what to do if it doesn't seem to be working.
Quick answer
- Frontline for cats contains fipronil: it kills adult fleas within about 24 hours and ticks within about 48 hours.
- Frontline Plus also contains (S)-methoprene, which stops flea eggs and larvae developing in your home.
- Apply it every 4 weeks for fleas. Frontline does not treat worms.
- Never use Frontline Tri-Act on cats: it is a dog product that contains permethrin, which is toxic to cats.
What is Frontline for cats?
Frontline is a range of flea and tick treatments made by Boehringer Ingelheim. Every Frontline product for cats contains fipronil, an insecticide that collects in the oil glands of the skin and spreads across the coat. Fleas and ticks are killed when they come into contact with it, so a flea does not need to bite for the product to work.
Frontline products for cats can be bought without a prescription from pet shops, pharmacies, supermarkets and online. That makes them convenient, but it also means you are responsible for choosing the right product and dose. Our main guide to flea treatment for cats compares Frontline with every other option.
Frontline for cats products compared
| Product | Active ingredients | Kills | Stops eggs hatching? | Age |
|---|---|---|---|---|
| Frontline Plus for cats (Frontline Combo) | Fipronil + (S)-methoprene | Fleas, ticks, chewing lice | Yes | From 8 weeks and 1 kg |
| Frontline Spot On for cats | Fipronil | Fleas, ticks, chewing lice | No | From 8 weeks and 1 kg |
| Frontline Spray | Fipronil 0.25% | Fleas, ticks, chewing lice | No | From 2 days old |
| Frontline Tri-Act | Fipronil + permethrin | Dogs only: toxic to cats | ||
Frontline Plus for cats
Frontline Plus for cats is the most popular version. Alongside fipronil, it contains (S)-methoprene, an insect growth regulator. Flea eggs laid by fleas on a treated cat do not develop into adults, which helps reduce the number of fleas building up in your carpets and furniture. It is the best Frontline choice for most cats. Frontline Plus is commonly sold in packs of 3 or 6 pipettes; the 6-pack usually gives the best price per month.
Frontline Spot On for cats
Frontline Spot On contains fipronil only. It kills adult fleas, ticks and lice but does not stop eggs developing, so you rely more on household treatment and vacuuming. It is usually slightly cheaper than Frontline Plus.
Frontline Spray for cats
Frontline Spray is a pump spray applied over the whole coat. Its big advantage is that it can be used on kittens from 2 days old, and the dose can be adjusted for very small or very large cats. Many cats dislike the noise and feel of spraying, and you must wear gloves and work in a well-ventilated room. The spray contains alcohol, so keep cats away from heat and flames until the coat is dry.
How to apply Frontline for cats
- Check the weight band on the pack. Cat spot-ons are usually one size for cats over 1 kg, but always confirm.
- Hold the pipette upright and snap off the tip.
- Part the fur at the back of the neck, just in front of the shoulder blades, until you can see the skin.
- Squeeze the entire contents directly onto the skin in one spot.
- Avoid stroking the area until dry, and stop other pets grooming it.
- Do not bathe your cat for 48 hours before or after application.
- Repeat every 4 weeks and note the date.
A greasy patch or a little clumped fur at the application site for a day or two is normal. If your cat licks the liquid, it may drool or foam briefly because of the bitter taste. This usually passes quickly, but contact your vet if it continues.
How long does Frontline take to work on cats?
Fipronil kills fleas on the cat within about 24 hours and ticks within about 48 hours. You will often see fleas for several weeks after starting treatment. These are new fleas hatching from pupae in your home, which then jump onto your cat and die. Keep treating every pet monthly for at least three months, vacuum daily and wash bedding at 60°C to break the cycle.
Why might Frontline not work on my cat?
Frontline is one of the most searched flea products, and "Frontline not working" is one of the most common complaints. There are several reasons:
- Application errors. The liquid must reach the skin. Applying onto thick fur, or onto a wet cat, reduces how well it spreads.
- Bathing or swimming. Washing within 48 hours can remove some of the product.
- Untreated pets. Every cat and dog in the home must be treated with a product suitable for its species.
- Untreated home. Up to 95% of fleas live in the environment as eggs, larvae and pupae.
- Gaps between doses. Leaving 6 weeks instead of 4 lets fleas start breeding again.
- Reduced effectiveness. Many UK vets now report that fipronil products seem less reliable than they once were. If you have done everything else correctly, ask your vet about a prescription product such as Bravecto for cats or Stronghold Plus.
Frontline for cats vs other flea treatments
| Frontline Plus | Advantage | Advocate | Bravecto spot-on | |
|---|---|---|---|---|
| Prescription | No | No | Yes | Yes |
| Fleas | Yes | Yes | Yes | Yes |
| Ticks | Yes | No | No | Yes |
| Stops eggs developing | Yes | Kills larvae in the environment | Kills larvae in the environment | Kills fleas before they lay |
| Worms | No | No | Roundworm and others | No (Bravecto Plus: yes) |
| How often | Every 4 weeks | Every 4 weeks | Every 4 weeks | Every 12 weeks |
If ticks are not a concern, Advantage flea treatment for cats is another popular non-prescription option. If you also want worm cover in one product, see Advocate for cats.
Effipro and Fiprotec: cheaper Frontline alternatives
Because the patent on fipronil has expired, several other brands sell the same active ingredient, often at a lower price:
- Effipro for cats (Virbac): fipronil spot-on, equivalent to Frontline Spot On.
- Effipro Duo: fipronil plus pyriproxyfen, which stops eggs and larvae developing, similar in principle to Frontline Plus.
- Fiprotec (Norbrook): fipronil spot-on.
- Fipronil sprays from several manufacturers, used in the same way as Frontline Spray.
These products work in the same way as Frontline, so the same application tips apply. Some cats do better on a different active ingredient altogether, which is something to discuss with your vet if fleas keep coming back.
Does Frontline treat worms?
People often search for "Frontline wormer for cats" or "Frontline dewormer", but Frontline does not treat any worms. If your cat has fleas, it may also have the flea tapeworm, which it catches by swallowing fleas while grooming. You need a separate wormer containing praziquantel, such as Drontal tablets or the Dronspot spot-on. Our cat worming guide explains how often to worm.
Is Frontline safe for cats?
Frontline products for cats are licensed and considered safe when used as directed. Possible side effects are usually mild:
- Temporary greasiness, clumping or hair loss at the application site.
- Itching or redness where it was applied.
- Drooling, foaming or brief vomiting if the cat licks it.
Danger: Frontline Tri-Act and other dog products. Frontline Tri-Act is licensed for dogs only and contains permethrin, which is highly toxic to cats. Signs of poisoning include twitching, trembling, wobbliness and seizures, and they can start within hours. Never use a dog product on a cat, and keep cats away from dogs treated with permethrin for at least 72 hours. If exposure happens, wash the area with washing-up liquid and warm water and contact a vet immediately.
Fipronil is also toxic to rabbits, so never use Frontline on rabbits.
Frontline for kittens and pregnant cats
Frontline Plus and Frontline Spot On are licensed for kittens from 8 weeks and 1 kg. Frontline Spray can be used from 2 days of age, which makes it useful for young kittens with fleas, though for very small kittens daily combing with a flea comb is often gentler. Frontline Plus is licensed for use in pregnant and nursing cats, but always check the current leaflet and ask your vet first. If you are expecting kittens, our cat pregnancy calculator helps you plan flea and worm treatment around the due date.
Where to buy Frontline for cats and how much it costs
Frontline Plus for cats typically costs £5 to £8 per pipette, depending on pack size and retailer, with 6-packs usually the best value. Generic fipronil spot-ons such as Effipro are often £3 to £5 per dose. Buy from reputable pharmacies, vets or well-known pet retailers to avoid counterfeit products, which have been sold online and may contain the wrong ingredients.
FAQs
Is Frontline Plus for cats good?
Frontline Plus for cats is a well-established, non-prescription treatment that kills fleas, ticks and chewing lice and also stops flea eggs developing. Many cats are protected well by it. However, many UK vets report that fipronil-based products seem less effective than they once were, so if fleas persist after correct monthly use, ask your vet about a prescription alternative.
How often should I use Frontline for cats?
For fleas, apply Frontline Plus or Frontline Spot On every 4 weeks. Protection against ticks may be shorter, so check the leaflet if ticks are a problem where you live. Use it all year round, as fleas breed indoors in winter.
Does Frontline treat worms in cats?
No. Frontline treats fleas, ticks and lice only. There is no Frontline wormer, so you need a separate cat wormer for roundworm and tapeworm. Cats with fleas often need a tapeworm treatment too.
Can I use Frontline on a kitten?
Frontline Plus is licensed for kittens from 8 weeks old and at least 1 kg. Frontline Spray can be used on kittens from 2 days old, following the dosing on the label. Ask your vet before treating very young or small kittens.
Why is Frontline not working on my cat?
The most common reasons are applying it onto the fur instead of the skin, washing the cat within 48 hours, the wrong weight dose, not treating other pets, and not treating the home. Fleas also keep hatching for weeks, so you may see some for 4 to 8 weeks even when the product is working.
Is Effipro the same as Frontline?
Effipro and Fiprotec contain the same active ingredient as Frontline Spot On (fipronil), and Effipro Duo combines fipronil with an egg-stopping ingredient, similar in principle to Frontline Plus. They are often cheaper.
Sources and further reading
This guide is for general information only and is not a substitute for advice from a vet. Medicines, doses and costs change: always follow your vet and the product leaflet. If your cat is unwell or you think it has eaten something toxic, contact your vet or an emergency vet straight away.
