Frontline Plus for Cats

Written By Mel Lee-Smith
Published: 07/12/2021Updated: 07/14/2021
Frontline Plus for Cats

Frontline Plus for cats is an over-the-counter parasite treatment that kills fleas and ticks at all life stages, as well as chewing lice. How effective is Frontline Plus for cats? How do you apply it? Keep reading for answers to these questions, as well as information on the average cost and side effects of Frontline Plus.


Unlike Frontline Plus for dogs, the cat version comes in only one dosage strength containing 9.8% fipronil and 11.8% S-methoprene. (We'll cover how these parasiticides work later in this article.)

Frontline Plus is available in packages containing 3, 6, and 8 doses, respectively. Each applicator contains a small amount of liquid, which is applied directly to your cat's skin. Apply one dose of Frontline Plus every 30 days for maximum protection against fleas and ticks. Frontline Plus is safe for cats over the age of 8 weeks and 1.5 pounds.

Application instructions

On paper, applying Frontline Plus for cats seems simple. Just take off the applicator, part the fur between your cat's shoulder blades, and squeeze the full contents of the packet onto a single spot on the skin.

In practice, however, giving a cat their meds can be tricky. Our feline friends can go into attack mode in the blink of an eye — especially if you try to wrestle them onto your lap and part their fur. Cats also groom themselves often. And while the product packaging might say that cats won't be able to lick the spot between their shoulder blades, any cat parent knows our fur-babies can achieve the seemingly "impawssible".

If your cat is especially stubborn, employ the help of a friend or another member of your household to apply the medication and supervise your cat until it dries. If you have an E-cone left over from a surgery, you might want to put it on your cat until Frontline Plus is dry. This is the best way to prevent an especially determined cat from licking the medication.

Early training is essential for keeping a cat calm while taking medication. If all else fails, contact your veterinarian for advice.


Frontline Plus is an inexpensive medication. Expect to pay $60 on average for a 6-month supply, or about $10 per dose.


.One study funded by Boehringer Ingelheim, the manufacturer of Frontline Plus found that Frontline Plus is 99.6% effective in killing fleas and ticks and preventing reinfestation within 8 days of treatment. The efficacy rate dropped to 85.6% on day 29, which is why treating your cat once every 30 days is essential for keeping them parasite-free. The study also observed no adverse effects associated with Frontline Plus.

Active ingredients in Frontline Plus for Cats

Frontline Plus for cats contains 9.8% fipronil and 11.8% S-methoprene.

Fipronil is a fast-acting, highly effective parasiticide that works in as few as 4 hours after application. In addition to killing fleas and ticks at their egg, larval, and adult life stages, fipronil is also used to kill chiggers and treat mange.

S-methoprene works together with fipronil to prevent parasites from coming back. It inhibits the growth of flea and tick eggs and larvae. In adult fleas, ticks, and other parasites, S-methoprene shuts down the reproductive processes.

Side effects

Side effects are rare and generally mild. Skin irritation at the application site is relatively common but not usually a cause for concern. Other side effects may occur if your cat ingests the medication, including:

Fortunately, these symptoms aren't usually serious and clear up quickly. Consult your vet if you notice any concerning side effects.


Generally, Frontline Plus is safe for cats and doesn't cause adverse effects or interact with medications. If you're concerned about whether Frontline Plus will be safe or effective for your cat, consult your vet to discuss your treatment options.

Drug interactions

Currently, no drug interactions with Frontline Plus for cats have been observed. If you have any questions about whether Frontline Plus will interact with one of your cat's current medications, consult your vet or chat with a vet live now.

Allergic reactions and sensitivity

While allergic reactions and sensitivity are rare, watch out for signs of an adverse reaction after applying. Your cat may experience skin irritation at the application site. If you notice signs of an allergic reaction, such as difficulty breathing or convulsions, contact your vet immediately.

Frequently asked questions

Help! My cat licked Frontline Plus before it dried — what should I do?

Fortunately, ingesting a small amount of Frontline Plus before it dries shouldn't cause severe symptoms for your cat. If your cat ingests Frontline Plus, follow the Pet Poison Helpline's guidance: provide fresh drinking water and feed your cat a small amount of palatable food. Once Frontline Plus dries fully, your cat can safely groom the application site.

What's the difference between Frontline and Frontline Plus for Cats?

Whereas Frontline Plus contains fipronil and S-methoprene, Frontline contains only fipronil.

S-methoprene prevents a reinfestation in your home by shutting down the reproductive system of adult fleas and preventing flea eggs from hatching.

How is Frontline Gold for cats different from Frontline Plus?

In addition to fipronil and S-methoprene, Frontline Gold also contains pyriproxyfen. This parasiticide has a similar mechanism of action to S-methoprene and inhibits the growth of eggs and larvae.

Frontline Gold is effective for 6 weeks instead of 30 days. It's also safe for kittens weighing more than 3 pounds, whereas Frontline Plus is suitable for kittens above 1.5 pounds.

Can I use Frontline Plus with other flea and tick treatments?

No. Combining Frontline Plus with other flea treatments isn't recommended. When used as directed, Frontline Plus provides full protection against fleas and ticks for 30 days.

I accidentally bought Frontline Plus for dogs. Can I use it on my cat?

No. Frontline Plus for dogs comes in higher dosage strengths that vary depending on the dog's weight. When purchasing parasite treatments for your pet, read the packaging carefully to ensure you choose the right product.

Is Frontline Plus safe for pregnant and lactating cats?

Yes, Frontline Plus is safe for all cats.

Is Frontline Plus waterproof?

Although Frontline Plus is waterproof once dry, it may take up to 24 hours for the medication to dry fully. Keep your cat indoors and away from water during this time to ensure maximum protection.

I've treated my cat, but I still see fleas in my home and yard. What should I do?

Even if fleas remain in the environment, they won't reinfest your cat as long as you apply Frontline Plus as directed. However, treating the environment is essential for your own comfort. Parasites that prey on your pets, especially ticks, can transmit serious diseases to humans, too, like Lyme disease.

To treat your indoor environment, wash all your bedding (including your pets') in hot water. Steam cleaners and indoor parasite control products work well. Try nematodes and diatomaceous earth to treat your yard and garden.

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