FRONTLINE SHIELD Flea & Tick Treatment for Medium Dogs, 21 - 40 lbs, 3 doses (3-Month Protection) -

Frontline Shield Flea & Tick Treatment for Medium Dogs, 21 - 40 lbs

By Frontline Shield
Rated 3.0909 out of 5 stars
Pet Weight

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$46.99Chewy Price
$52.99Chewy Price
$44.64Autoship Price
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About This Item


  • Helps kill ticks, stable flies, chewing lice and adult fleas, flea eggs and larvae.
  • Topical solution helps to repel ticks that may transmit Lyme disease and mosquitoes that may transmit heartworm disease.
  • Helps prevent reinfestation by stopping all flea life stages from developing.
  • Each dose is formulated to protect your dog for a full 30 days.
  • The treatment is easy to apply and is waterproof 24 hours after application.

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Play Video: Learn More About Frontline Shield From Our Team of Experts
Learn More About Frontline Shield From Our Team of Experts

About FRONTLINE Shield for Dogs

The #1 Name in Flea and Tick Protection*

FRONTLINE Shield is powerful 3-in-1 protection for dogs. It not only kills fleas and ticks—it also repels mosquitoes, ticks and stable flies. Just one dose provides protection for a full 30 days.

Breaks the Flea Life Cycle

FRONTLINE Shield kills existing adult fleas as well as flea eggs and larvae. Once applied, it rapidly spreads over the surface of your dog’s body. One application provides continuous flea and tick protection for a full month and helps prevent future infestations.

Protect Your Dog So You Can Go Anywhere Together

Fleas and ticks can be found everywhere outdoors—the park, the lake, even your own backyard. That’s why monthly protection is so important.

From the #1 Name

FRONTLINE is the #1 name in flea and tick protection.*

Repellency Power

Repels ticks, mosquitos and stable flies, so they won’t bug your pet.

Kills Fleas and Ticks

FRONTLINE Shield kills fleas, ticks and chewing lice.

Powerful Defense

Repels ticks that can carry Lyme disease and mosquitoes that may transmit heartworm disease.

Trusted Protection

FRONTLINE brand products are the flea and tick protection products pet parents trust most.*


FRONTLINE Shield becomes waterproof 24 hours after application, for lasting protection.

Effective for Puppies

Can be used on puppies as young as 9 weeks old who weigh at least 5 lbs.

For Dogs Big and Small

Doses come in Extra-Small 5-10 lbs., Small 11-20 lbs., Medium 21-40 lbs., Large 41-80 lbs., and Extra-Large 81-120 lbs.

Fleas and Ticks Abound Year-Round

No matter the time of year, fleas and ticks can pose a threat to your dog. Flea infestations usually begin 6-8 weeks before you ever see a flea, and once you have a flea problem, it can take 90 days or more to fully eradicate. That’s why you need monthly protection year-round with FRONTLINE Shield.

Year-Round Protection With Autoship

Sign up for Autoship today and save on FRONTLINE Shield. You’ll get a discount on every order, and you can rest easy knowing you’ll never run out of your dog’s flea and tick protection.

Dedicated to Prevention

Boehringer Ingelheim, the maker of FRONTLINE Shield, is committed to enhancing pet well-being and supporting the animal health community through science and innovation. No pet should have to suffer a preventable disease, which is why Boehringer Ingelheim develops product lines like FRONTLINE, the flea and tick protection brand most trusted by pet parents.* 

About FRONTLINE Shield

FRONTLINE Shield protects your dog from fleas and ticks. Three powerful ingredients combine to kill fleas, ticks and chewing lice fast—and continue protecting your dog for a full 30 days. A single topical application of FRONTLINE Shield also repels stable flies, ticks that may transmit Lyme disease, and mosquitoes that may transmit heartworm disease. It’s the monthly protection your dog needs, from the brand you trust.


*Data on file at Boehringer Ingelheim.

Questions & Answers

3 Customer Questions

Does this kill fleas, ticks, flies, and mosquitos before they bite the dog?
Answer by ChewyMar 21, 2021
This treatment kills fleas, ticks, and chewing lice as well as repels mosquitoes, ticks, and stable flies.

can two dogs take this

Is this product safe for a 4 month old puppy weighing 22 lbs
Answer by ChewyJul 04, 2021
This treatment is suitable for dogs 9 weeks of age and older, within the corresponding weight range.

ReviewsWrite a Review

Rated 3.0909 out of 5 stars
11 Reviews
Would recommend to a friend

11 Customer Reviews

Filter by reviews that mention

Rated 1 out of 5 stars
By Kerry on Nov 28, 2022

Does Not Work

Do not I repeat please do not use this new and improved protection. My dog almost died because she was bitten by a tick and got Lymes disease

Rated 5 out of 5 stars
By PupLuv on Sep 6, 2022

Works great!

It's been a while since I've had a dog and wasn't sure which flea & tick prevention to use on my puppy. I did my research on Chewy and decided to give Frontline Shield a try. Fleas & ticks gross me out so I wanted to be sure and get him started when he was old enough and keep up with it every month. So far so good! Also like that it helps with mosquitoes - I don't like them biting me so it makes sense he wouldn't either!

Rated 5 out of 5 stars
By MochisMom on Sep 6, 2022

Great flea and tick product

My dog Lucky loves being outside. We live in an area with A LOT of mosquitoes so I'm glad I found a product that kills fleas and ticks AND repels mosquitoes! Now Lucky can play outside and I don't have to worry.

Rated 5 out of 5 stars
By CorgiLove on Aug 4, 2022

Dog seems happy

I'm not expert but the dog seems happy and I haven't spotted as many fleas and ticks as in past summers so that's a win for me. I love the applicators because they are easy to use.

Rated 4 out of 5 stars
By BagelBulldog on Jul 19, 2022

Great product

My dog loves playing outside, and this product helps protect him from fleas, ticks AND mosquitoes.

Rated 1 out of 5 stars
By lousyshopper on Jul 16, 2022

Didn't notice toxicity

money down the drain... We have cats ...............

Rated 1 out of 5 stars
By violet on Oct 10, 2021

didnt work

put in on didnt work i am going to take her to vet to see what he can give her to help ,you all have been so good to me,always nice and helpful

Rated 1 out of 5 stars
By Charlene on Sep 28, 2021

Flea meds don’t work

This flea medicine doesn’t seem to work. My dogs are still scratching and seem very uncomfortable. I won’t be purchasing this brand anymore.

Rated 1 out of 5 stars
By Frontline on Sep 22, 2021

Stopped working in less than a week

Dogs still have fleas!!! Thought this was a stronger better Frontline. Very disappointed in this product.

Rated 5 out of 5 stars
By Dixie on May 21, 2021

Great product!

I was apprehensive to use a topical flea and tick product. But here in Fl it is a year around problem and I have tried shampoo’s, sprays, over the counter products and none worked. It was either a topical or a pill. This works great!