Applying topical treatments to your cat

Most people look this up when they’re holding a little tube of “spot-on” or a medicated cream and wondering: where, exactly, does this go on a cat — and what happens if they lick it. The stakes are simple and real: the right product, in the right place, can prevent parasites and calm irritated skin; the wrong product (or the wrong technique) can make a cat unwell.

Below are the practical checks that matter, the safest way to apply common topical treatments, and the mistakes that cause most problems — especially in Australian homes where fleas are persistent and paralysis ticks can be life-threatening in some regions.^{1, 2}

What “topical treatment” means (and what it doesn’t)

A topical treatment is any medication applied to the outside of your cat’s body — usually onto the skin, not the fur. It can be used to prevent parasites (like fleas and ticks) or to treat certain skin conditions.

Topicals are not interchangeable. A product made for dogs can be dangerous for cats, even when the dose seems small.^{4, 5}

Common types of topical treatments for cats

1) Spot-on parasite preventatives (fleas, ticks and sometimes worms)

These come in single-use pipettes and are applied to the skin at the base of the skull or on the back of the neck, where a cat can’t easily lick. Some products are monthly; others last longer — always follow the label for your exact product.^{3, 6, 8}

2) Medicated shampoos and rinses

These are used for specific skin problems and are not a substitute for flea control unless your vet has advised it. Shampoos also wash away natural oils and can irritate already-inflamed skin if used too often.

3) Creams/ointments for local skin issues

Antifungal or antibacterial creams may be prescribed for small, localised areas. Cats groom. If a product isn’t labelled as safe when licked (or your vet hasn’t told you it is), assume you’ll need to prevent licking until it’s absorbed.

Before you apply anything: quick safety checks

• Confirm it’s for cats. “For dogs only” products should never be used on cats.^{4, 5}
• Check the weight range and age on the label and use the correct pack for your cat’s current weight.^{1, 6}
• Don’t stack parasite products (two spot-ons, or a spot-on plus a collar, etc.) unless your vet has told you the combination is safe.
• Plan for grooming. Many “reactions” are actually licking: drooling, foaming and nausea can happen when a cat tastes spot-on solution.^{3, 7}
• If the skin is broken or infected, pause. Some spot-ons should not be applied to skin lesions — check the label and call your vet if you’re unsure.⁸

How to apply spot-on treatments safely (step-by-step)

This method suits most flea/tick “spot-on” products.

1. Choose the right location. Aim for the base of the skull/back of the neck — a spot that’s difficult to lick.^{2, 8}
2. Part the fur until you can see skin. The liquid needs to reach the skin to work properly.^{6, 8}
3. Place the tip on the skin and empty the pipette as directed. Some products are applied in one spot; larger cats may need two spots (follow your label).⁸
4. Keep your cat (and other pets) from grooming the area while it dries. If you have multiple cats that groom each other, separate them until the application site is dry.^{8, 5}
5. Wash your hands after. Even if you didn’t use gloves, treat it like a medicine.

A small detail that makes a big difference

Spot-on products spread through the skin’s natural oils. If you drip it onto fur, much of the dose can end up on the coat — and then on tongues, bedding, and your hands.

Making the application easier (without wrestling)

• Pick a quiet moment. After a meal or a play session, many cats are calmer.
• Use a stable surface (floor, not a slippery bench) and keep movements slow.
• Pre-part the fur with one hand before bringing the pipette in, so you can apply in one smooth motion.
• Reward afterwards with something that doesn’t require face-rubbing (a small treat is better than chin scratches while it’s wet).

Common mistakes to avoid

• Using dog products on cats. Some ingredients (including permethrin) are well known for causing serious toxicity in cats.^{4, 5}
• Applying in the wrong place. If your cat can lick the wet product, you’re more likely to see drooling, vomiting or agitation.^{7, 8}
• Assuming indoor cats don’t need flea control. Fleas and their life stages can build up in the home environment, and the household needs a whole-of-home plan during an infestation.^{9, 10}
• Not treating all pets in the household. Leaving one untreated animal can keep the cycle going.⁹
• Applying “more for extra protection”. More dose does not mean more effective — it only increases the risk of side effects.

How often should you apply topical treatments?

There isn’t one correct schedule. It depends on the product, your cat’s weight, and local parasite risk. Many flea spot-ons are monthly, while some newer spot-on products can last longer — the label is the authority for timing and dose.^{6, 8}

If fleas are already established in your home, topical treatment alone may not feel like it’s “working”, because most of the flea population is often in the environment (eggs, larvae and pupae in carpets and bedding). Environmental cleaning and treatment is usually needed to break the cycle.⁹

Tick country: topical treatments are helpful, but searching still matters

In areas where paralysis ticks occur, prevention products reduce risk but don’t remove it entirely. Regular tick searches are still recommended, and any suspected tick paralysis is an emergency.^{1, 2}

• Check your cat daily (more often in high-risk coastal scrub areas).^{1, 2}
• Seek veterinary care immediately if you find a paralysis tick or notice worrying signs (weakness, wobbliness, breathing effort, change in voice).²

Possible side effects (and when to call the vet)

Most cats tolerate topical parasite products well when used correctly, but side effects can happen.

• Common, usually mild: brief drooling/foaming (often from tasting it), temporary itchiness at the site, mild gastrointestinal upset.^{7, 6}
• Concerning: tremors, weakness, unsteady walking, marked agitation, seizures, breathing difficulty, or collapse — especially after exposure to dog tick/flea products. Treat these as urgent and contact a vet or a poisons advice service immediately.^{5, 7}

Final thoughts

Topical treatments work best when they’re treated like medicine, not grooming. Use the right product for cats, apply it onto skin at the back of the neck, and give it time to dry without grooming. If parasites persist, look beyond the cat’s coat — the house often holds the larger share of the problem.^{9, 10}

References

1. University Veterinary Teaching Hospital Sydney (The University of Sydney) – Tick paralysis
2. RSPCA NSW – Tick season: protecting your pet
3. Merck Veterinary Manual – Ectoparasiticides used in small animals
4. RSPCA Knowledgebase – How do I stop my companion animal from getting fleas?
5. American College of Veterinary Pharmacists – Pet Poison Control: Permethrin
6. University Veterinary Teaching Hospital Sydney (The University of Sydney) – Complete parasite protection
7. Animal Poisons Centre (Australia) – Flea and tick spot-on: safe application and risks for pets
8. Bravecto Australia – Bravecto Spot-on for Cats: how to apply
9. RSPCA Australia – Understanding fleas and their impact on companion animals
10. Exelpet Australia – Vet Series Spot-On Flea Treatment for All Cats (directions and frequency)