Tick prevention for dogs and cats

Tick prevention for pets works by one of two routes: repelling the tick before it bites, or killing it soon after it attaches, before it has fed long enough to pass anything on. All three formats below rely on an active ingredient absorbed into the skin’s oils or bloodstream, which is why correct dosing and a consistent schedule matter more than the format you pick.

The options

Format	How it works	Upside	Downside
Spot-on	Liquid between the shoulder blades, monthly	Easy to apply, widely available, many also cover fleas	Keep other pets away until dry; can irritate sensitive skin
Tick collar	Releases active ingredient over months	Long protection, low effort	Must sit snugly; not ideal for pets that lose collars
Oral chewable	Flavoured tablet, monthly or quarterly	Nothing on the coat, unaffected by swimming	Usually prescription only; the tick must bite before it dies

Cats are not small dogs. Permethrin, used in many dog products, is toxic to cats, even from close contact with a treated dog before the product has fully dried. Only use a product labelled for the species, and never apply a dog spot-on to a cat.

Permethrin poisoning in cats is a genuine emergency, not a mild irritation. Signs include tremors, drooling and loss of coordination, and it can be fatal without prompt veterinary treatment. If a permethrin product is ever applied to a cat by mistake, or a cat has close contact with a wet-treated dog, contact a vet immediately rather than waiting to see if symptoms appear. This risk is one reason multi-pet households need to keep species-specific products physically separate, and to let a treated dog dry fully before letting it near a cat.

Choosing between the formats

A spot-on is the most common starting point because it needs no daily thought once applied, but it takes time to spread through the coat’s oils, so avoid bathing a pet for a day or two either side of application. Collars suit pets that tolerate wearing one and give the longest single application, though a loose or chewed collar loses effectiveness. Oral chewables are appealing for pets that swim often or get bathed frequently, since nothing sits on the coat to wash off, but most require the tick to bite before the active ingredient reaches it, so they are a “kill soon after attachment” product rather than a true repellent.

None of these is available over the counter in every country in the same form; a product sold as a spot-on in one market may only be available as a prescription chewable elsewhere, so ask a vet what is registered and appropriate locally rather than importing a product bought overseas.

Getting the most from any product

• Dose by current weight: under-dosing is a common reason products seem to fail, and weight can change between renewals, especially in growing or ageing pets.
• Keep to the schedule: gaps between doses are when bites happen; set a reminder rather than relying on memory.
• Check the label against the species: every year, cats are harmed by a dog product applied by mistake or through contact.
• Ask a vet before combining products: some flea, worming and tick treatments should not be layered without guidance.
• Keep checking by hand: no product stops every tick, so run your hands through the coat after time outdoors, paying attention to where ticks tend to hide on pets.

If you do find an attached tick despite prevention, the removal method matters as much as the prevention did: see how to remove a tick from a dog and use Live Scan if you want a closer look at what you have pulled off. For the signs a bite has caused a problem, tick disease signs in pets covers what to watch for over the following days.