How Long Does Frontline Take to Work?

When it comes to controlling fleas and ticks, FRONTLINE Brand Products are the #1 recommendation of veterinarians for flea and tick control for dogs and cats.

These tiny, almost-invisible pests can make life miserable and disrupt your household with a vicious cycle of biting and scratching. And with an added ingredient to kill flea eggs and larvae, FRONTLINE Plus completely breaks the life cycle of these dangerous and annoying pests.TicksOften too tiny to be seen, ticks attach to pets and feed on blood until they are engorged.

Our research data shows FRONTLINE Brand Products will kill fleas within 18 hours of contact with your treated pet. FRONTLINE Brand Products kill fleas and ticks if they simply come into contact with your pet’s hair coat. FRONTLINE Brand Products make fleas hyper excited, drawing them to the top of the haircoat before dying.

Consecutive monthly applications of a FRONTLINE Brand Product to your pet will assist with the elimination of an indoor flea life cycle. Our research data indicates that FRONTLINE Brand Products, when used monthly, will kill your pet’s fleas within 18 hours of application – before they can lay eggs. We recommend storing FRONTLINE Brand Products at room temperature and keeping them sealed in their original packaging.

If a FRONTLINE Brand Product is to be applied after a bath, make sure the pet is completely dry before application. FRONTLINE Brand Products are available in three formulations to make it easy for you to provide your pet with the flea and tick control that is best for them. Research results show that FRONTLINE Brand Products control fleas and ticks for a full month, so reapplication is unnecessary within 30 days.

How long does it take for fleas to die after Frontline?

If you’ve treated your pet with FRONTLINE Spot On or FRONTLINE Plus those fleas will die within 24 hours, and so will have few opportunities to lay eggs (egg laying normally starts 24 hours after feeding), helping you control the infestation in your home.

Why do I still see fleas after using Frontline?

A. The active ingredient in FRONTLINE (fipronil) kills fleas by affecting their nervous system, making them hyperactive before dying. These dying fleas often rise to the top of your pet’s haircoat, so the presence of visible fleas after treating your pet, is a sign that the product is working.

How long does it take Frontline to become effective?

Frontline Plus will get rid of all fleas within 18 hours of contact with your pet and will kill all ticks within 48 hours after coming in contact with your pet. Frontline Plus covers your pet’s whole body within 24 hours of application. It spreads on your pet’s body through a process called translocation.

Why is Frontline not working?

If you suspect it is not controlling your pet’s fleas, you may, in certain cases, be able to reapply it in as little as two weeks and try again. Speak to your veterinarian about this first if your flea medicine is not working. One Frontline alternative is to switch to another topical product.

Frontline Plus is a topical product — which means it’s applied to the skin rather than ingested or injected — used to kill fleas and ticks. Frontline Plus kills adult fleas and ticks as well as flea eggs and larvae, and lice.

It has come to my attention that at certain times of the summer, fleas on dogs and cats can become plentiful. Sometimes, despite your best efforts to control them, the flea-control products you use do not always appear to be working as well as in previous months or even years. The painful reality is that regardless of the product chosen for your dog or cat, there are times when flea populations in the surrounding environment sky-rocket and jump onto your pet with daily frequency and in high numbers. No product works like a Teflon shield to deflect new fleas from getting on your furry friend. Actually, on a well-protected pet, the fleas you see today are not likely the ones you will see tomorrow. In fact, fleas that have jumped on a Frontline Plus treated pet have long begun the process of dying by the time you visualize them on your pets belly or forehead. Even so, the mere sight of them can be disturbing. To make matters worse, new fleas will hop on whenever the pet visits a flea-riddled area in its environment be it outside or in. To the untrained eye, this leads to the perception of catastrophic product failure because you begin to see fleas every day. I would like to offer some perspective that might prove useful to understanding flea control and which I hope can help reduce the frustrations that arise when flea populations grow.

Many hundreds of egg-laying female fleas contribute to breeding ground hotspots in cool, dark (shady), protected micro-climates within homes (beneath sofa cushions, pet hiding places, garages, basements, etc.) As each of these flea-infested animals enters your property and beds-down, rests or takes up residence, flea eggs fall off their hair coats (envision a salt-shaker) into those dark, humid, and out-of-the-way areas.

When using a topical flea preventative that is put on top of the skin, it is ideal to use a product that contains an insect growth regulator (IGR) like (S)-methoprene and this is where the PLUS comes in when we speak of FRONTLINE Plus.

Frontline Plus will get rid of all fleas within 18 hours of contact with your pet and will kill all ticks within 48 hours after coming in contact with your pet. Frontline Plus covers your pets whole body within 24 hours of application. It spreads on your pets body through a process called translocation. In translocation, Frontline Plus is accumulated inside the oil glands after which it gradually flows out and coats your pets fur over the next 30 days.

Ticks usually look for warm, damp places to hide and may crawl inside your dogs groin, ears, or under his front legs. Fipronil particularly affects receptors that receive signals that keep the nervous system of ticks and fleas relaxed.

Your pet will not experience any severe side effects if it is healthy, is not allergic to any of the main ingredients, and is given the correct dosage of Frontline Plus monthly. Lethargy Excessive salivation Vomiting or severe diarrhea Swelling of the face, lips, or tongue Uncoordinated movements Coma Rash or hives Seizures


Frontline Plus begins killing fleas as soon as four hours after being applied to the skin, according to a study published in the “The International Journal of Applied Research.” The study shows that 100 percent of fleas were dead 12 hours after application.