Flea and tick prevention for dogs

Most vets recommend flea and tick prevention for dogs all year round, for life, given exactly as often as the product says: usually monthly for spot-ons and chews, every three months for some chews, and every few months for long-lasting collars. The Companion Animal Parasite Council (CAPC) recommends that all dogs be treated year-round to stop infestations taking hold in the home.

The product matters less than the habit. A gap of a few weeks is how fleas get a foothold and ticks get time to pass on disease. Here is how prevention works, the main types, and the safety rules worth knowing.

Why fleas and ticks are worth preventing

What fleas do

Fleas are more than itchy. According to CAPC, they can cause:

• Flea allergy dermatitis, an intense allergic itch from a few bites
• Anaemia from blood loss in heavy infestations, which can be serious in puppies and small dogs
• Tapeworm, which dogs catch by swallowing fleas while grooming
• Infections that can reach people, including the bacteria behind cat scratch disease and flea-borne typhus

What ticks do

Ticks carry some of the most serious infections dogs can get. CAPC lists:

• Lyme disease
• Anaplasmosis
• Ehrlichiosis
• Rocky Mountain spotted fever
• Babesiosis

Which ones matter depends on where you live and travel. Timing matters too: Lyme bacteria usually need 24 to 48 hours of feeding to pass to a dog, while some other infections can pass within 3 to 6 hours of a tick attaching. That is why products that kill ticks fast, and checking your dog after walks, both help.

Why year-round, even in winter

It is tempting to stop in autumn. Most vets advise against it:

• Fleas live indoors. Eggs fall off your dog within hours and develop in carpets, under furniture and in bedding. In a heated home, the cycle carries on all winter.
• Flea cocoons wait. CAPC notes that flea pupae can lie dormant for months in cool conditions, then hatch when warmth and a host return.
• Ticks don’t keep a calendar. Some ticks are active whenever the weather is mild, including warm winter days.
• Gaps are easy to forget. A product you give every month is far easier to remember than one you restart each spring.

How often: the main types compared

Your vet will help you choose. Products differ in what they cover, how long they last and how they are given.

Many modern products cover both fleas and ticks, and some combine flea, tick, heartworm and worm protection in one dose. If you live where heartworm occurs, ask about a combined product; see our heartworm prevention guide.

Safety rules that matter

• Use the product for your dog’s current weight. Doses come in weight bands. Weigh your dog if you are unsure, especially puppies, which grow out of a band quickly. Don’t split or share a pack between dogs unless your vet tells you to.
• Respect the minimum age. Each product states the youngest age and lowest weight it is safe for. CAPC recommends starting prevention as early as the label allows.
• Never put a dog product on a cat. Some dog spot-ons contain permethrin, which is highly toxic to cats. International Cat Care warns it can cause twitching, tremors and seizures. If you have cats, choose a dog product without permethrin, keep cats away from a freshly treated dog, and call a vet straight away if a cat is exposed.
• Tell your vet about seizures. The FDA has warned that a widely used class of oral flea and tick products (isoxazolines) can cause neurological effects such as tremors, wobbliness and seizures in some dogs. Most dogs have no problem, but your vet will want to know about any history of seizures before choosing one.
• Buy from a source you trust. Counterfeit and grey-market flea products exist. Your vet or a reputable pharmacy is the safe route.
• Watch for reactions. Mild redness where a spot-on was applied can happen. Vomiting, drooling, tremors or wobbliness after a dose need a call to your vet.

Treat every pet in the house

Fleas move between animals. CAPC is clear that every dog and cat in the home must be treated to control an infestation, each with a product made for its species. Treating only the itchy one leaves the others as a flea reservoir.

If your dog already has fleas

Signs include scratching, nibbling at the base of the tail, and flea dirt: black specks in the coat that turn reddish-brown on damp white paper (it is digested blood).

1. Start or restart a proper flea product for every pet.
2. Wash bedding hot and vacuum floors, sofas and the car often, emptying the vacuum outside.
3. Keep going on schedule. New fleas will keep hatching from the home for weeks, and CAPC notes a moderate to heavy infestation can take several months to bring fully under control.

If your dog’s skin is red, sore or broken, or the itching started before you saw any fleas, see your vet: our guide to dog itching and scratching covers the other causes.

Checking for ticks

After walks in long grass, woodland or moorland, run your hands over your dog, paying attention to the head, ears, neck, armpits, between the toes and around the tail. Ticks feel like a small, firm bump. Remove one promptly with a tick tool or fine-tipped tweezers, without squeezing or twisting the body; our guide on how to remove a tick from a dog shows the technique. In areas with Lyme disease, ask your vet about a Lyme vaccine as well; see the adult dog vaccination schedule.

Making it a habit

The best flea and tick prevention is the one given on time, every time. Pick a date that is easy to remember, such as the first of the month, and keep the pack where you will see it. PetTrackr can put the dose on your dog’s daily plan and remind you, and if someone else in the family gives it, everyone can see it has been done.