How quickly does it work?

Adult fleas die within 24 hours of contact, ticks within 48, and the (S)-methoprene stops eggs and larvae developing — attacking the 95% of the infestation you can't see.

Why do I still see fleas afterwards?

Eggs already in your home keep hatching for weeks — new arrivals die on your treated dog. It's the treatment working, not failing. Heavy infestations also need a household spray.

How often do I apply it?

Monthly, onto skin between the shoulder blades. Avoid bathing for 48 hours around application.

What if my dog is on the weight boundary?

Weigh, don't guess — the dose is matched to 20–40kg. Border-line dogs should use the size their current weight puts them in, rechecking as they grow.

Frontline Plus Large Dog - 3 Pipettes

Frontline Plus for large dogs (20–40kg) — kills fleas within 24h and ticks within 48h, and stops flea eggs and larvae developing. 3 pipettes = 3 months.

Kills fleas within 24 hours.
Kills ticks within 48 hours — and lice.
Stops flea eggs and larvae developing.
For dogs 20–40kg — 2.68ml pipettes.
3 pipettes = 3 months' protection.

£27.89 GBP inc. VAT

In stock

Safety information 3

Dose by your dog's weight

Each size delivers a weight-matched dose — weigh your dog and use the right pack. Not for puppies under 8 weeks or under 2kg.

Keep pets apart until dry

Apply where the dog can't lick — base of neck between shoulder blades — and keep treated pets away from children and other animals until the application dries. Wash hands after.

Fleas seen after treatment are normal

New fleas from the environment keep hatching for weeks — they die on the treated pet. Treat the home too for heavy infestations.

Product overview

About Frontline Plus Spot-On — Large Dog

Frontline Plus is the vet-familiar flea treatment for dogs in its large-dog dose: 3 pipettes of 2.68ml for dogs 20–40kg. Fipronil kills adult fleas within 24 hours, ticks within 48, and lice — while (S)-methoprene, the 'Plus', stops flea eggs and larvae developing, breaking the reinfestation cycle other treatments leave running. 3 pipettes = 3 months of monthly protection.

Why the Plus matters

Adult fleas are 5% of an infestation — the other 95% is eggs and larvae seeded through your carpets. Killing adults alone invites the next wave; Frontline Plus's insect growth regulator sterilises the pipeline, which is why it remains the benchmark spot-on. Ticks matter too: 48-hour kill shortens the disease-transmission window.

How to apply

Weigh the dog (this dose is for 20–40kg), part the coat between the shoulder blades, and empty the pipette onto skin — not fur. Reapply monthly. Don't bathe within 48 hours of application; keep the spot unlickable and dry.

Good to know

Fleas appearing days after treatment are environmental hatchlings dying on contact — normal, not failure. Persistent infestations need the house treated as well (see Frontline Homegard).