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10 Best Flea Drops for Dogs in 2021 – Reviews & Top Picks

Frontline Plus for Dogs Small Dog (5-22 pounds) Flea and Tick Treatment

Discovering fleas on your furry companion is like finding a ticking time bomb strapped under your bed. The problem must be dealt with quickly. You don’t have the luxury of testing products to see which one works.

If the first product you choose fails, you may be in big trouble. A house full of multiplying pests can be more than just a nuisance—it can be a health hazard.

To make sure that you’re covered in case of such an occurrence, we’ve tested all of the popular flea and tick treatments on the market to determine which ones won’t let you down when it counts.

The following reviews will compare the top ten, and the number one position holds the one that we trust the most.

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Our Favorite Picks of 2021 Compared:

Image Product Details
Best Overall
Bayer K9 Advantix II Bayer K9 Advantix II
  • Feature iconWorks for 30 days
  • Feature iconKills within 12 hours
  • Feature iconContains 6 monthly applications
  • Best Value
    Second place
    Hartz Hartz
  • Feature iconVery affordable
  • Feature iconPrevents re-infestation for 30 days
  • Feature iconFull body protection
  • Premium Choice
    Third place
    Frontline Plus Frontline Plus
  • Feature icon6 doses to last 6 months
  • Feature iconSeparate ingredients to kill adults and larvae
  • Feature iconWorks for 30 days
  • TevraPet Activate II TevraPet Activate II
  • Feature iconAffordably priced
  • Feature icon4-month supply
  • Feature iconKills and repels
  • Sentry FiproGuard Sentry FiproGuard
  • Feature iconAffordable
  • Feature icon3-month supply
  • The 10 Best Flea Drops for Dogs:

    1. Bayer Advantix Flea Prevention Dog Drops – Best Overall

    Bayer Animal Health

    For fast-acting and long-lasting relief for your canine partner, the Bayer K9 Advantix II flea prevention is our top recommendation. We had great luck with this one and it seemed to live up to all expectations. Lice, fleas, and ticks will be killed within just 12 hours. Once applied, the Advantix formula continues to work for 30 days, so you don’t have to keep reapplying, and you don’t have to worry about whether your dog is protected. Moreover, biting flies and mosquitoes will be repelled to help keep your dog nice and comfortable.

    This package contains six applications to be applied in 30-day intervals, so it will last six months. It’s a bit pricey as it’s one of the more expensive options. That said, it’s one of the more effective options. We feel that our money is well spent on this product, which is why it has earned our highest recommendation on this list.

    • Works for 30 days
    • Kills within 12 hours
    • Contains 6 monthly applications
    • Pricey
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    2. Hartz Topical Flea & Tick Prevention for Dogs


    Despite being one of the most affordable methods of flea and tick prevention, the Hartz UltraGuard Dual Action topical is one of the best choices for keeping your dog free of pesky pests. Even though it’s priced so cheap, you still get three separate applications to last for three months of protection. While this isn’t as many as some other brands, it’s hard to complain with such a low price tag.

    This formula protects your dog’s whole body. It kills and prevents re-infestation from head to toe, so you can rest assured that your dog is taken care of. That said, we didn’t like the extremely strong odor that it left on our dogs. The smell dissipates over a few days, but we found it to be unpleasant. That said, we think it’s one of the best flea and tick preventions that we tested, and its affordability helped it to land our second place recommendation.

    • Very affordable
    • Prevents re-infestation for 30 days
    • Full body protection
    • Extremely strong chemical smell
    • Only 3 applications included
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    3. Frontline Plus Flea Treatment for Dogs


    Thanks to the completely waterproof formula of the Frontline Plus Flea Treatment, it only needs to be applied once a month to keep your dog fully protected. It’s effective at killing fleas, flea eggs, lice, and ticks, so your dog will be covered from the bulk of the nasty pests that you might be concerned about. Each box has enough doses to last six months, so you won’t need to re-supply very often. This is a good thing since the price per package is pretty high.

    This formula features two separate killing ingredients to make sure larvae and adults are handled completely. We didn’t like the oily residue that was left behind on our dogs, but this is necessary for the repelling of pests. Overall, we think it’s one of the better options, though it doesn’t provide quite the same bang for your buck that the Bayer K9 Advantix in our top position did.

    • 6 doses to last 6 months
    • Separate ingredients to kill adults and larvae
    • Works for 30 days
    • Premium price
    • Leaves an oily residue
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    4. TevraPet Activate Dog Flea & Tick Prevention


    Though it contains the same active ingredients as the K9 Advantix II, we didn’t get the same performance from the TevraPet Activate II flea and tick prevention drops. It seems like it may not contain the same amounts of those ingredients because it was just not as effective as the Bayer product. Of course, it’s also much lower-priced, so we didn’t expect it to perform at the same level. It did have a positive effect, just not as pronounced as we’d prefer.

    For the low price, you get a four-month supply. This is one of the better deals, but with the reduced effectiveness, it’s a tradeoff we’d rather not make. Worse, some of our dogs had an adverse reaction and seemed to dislike these drops once applied. Our dog was anxious and began whining incessantly once we used the drops. After seeing this reaction, we weren’t comfortable using this product on our other dogs. However, we had already used it on several dogs without any adverse reactions and it was semi-effective with them.

    • Affordably priced
    • 4-month supply
    • Kills and repels
    • Some dogs had a poor reaction
    • Wasn’t as effective at killing fleas
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    5. Sentry FiproGuard Topical Flea Drops for Dogs


    Available in a three-month supply, the Sentry FiproGuard 2950 topical flea drops are one of the most affordable flea drops for dogs that we tried. Buying it once and not having to think about it again for a quarter of a year is very appealing to us, but unfortunately, this product wasn’t effective enough to merit our recommendation. It is waterproof and shouldn’t wash off of your dog. But unlike other medications we tried, this one didn’t leave any visible signs of application except for the terrible smell. We didn’t like how it made our dogs stink, but we could have gotten over that for exceptional performance.

    We did notice a reduction in pests, but it didn’t cure the flea problem we had purchased it to solve. Other products were several times more expensive though, so we were hoping for the best with the Sentry FiproGuard. In the end, it let us down, though it’s not the worst choice of the bunch.

    • Affordable
    • 3-month supply
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    6. CrossBlock II Flea Preventative for Dogs

    WIM CrossBlock II

    Initially, we were attracted to the very low price of the CrossBlock II Flea preventative. After testing, we don’t think it’s a good choice when compared to other options on the market for the simple fact that it’s not reliably effective. The performance it provides is spotty, at best. In some cases, we saw results in reducing the number of active fleas on our dogs, but they returned in short order. In another test, we didn’t get any noticeable reduction at all. In both cases, it failed to work on ticks since we still found several while using this product. Even though it’s a very small investment, we don’t think the value is there since it simply didn’t work well enough to recommend.

    • Cheap
    • Spotty performance
    • Didn’t work for ticks
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    7. Advecta Dog Flea & Tick Topical Treatment


    We liked the sound of the 5-way protection that the Advecta flea and tick topical treatment promised to provide for our dogs. Offering safety from fleas, ticks, biting flies, mosquitoes, and lice is enticing, but it didn’t manage to perform this feat well enough to climb our list and earn a recommendation. We did see a slight reduction in the number of pests over the first few days, but they were quickly replaced and came back stronger than before just a few days later.

    The worst issue was that it made some of our dogs sick, and we had to deal with some unpleasant stomach issues including vomiting and diarrhea. It is priced pretty affordably for a four-month supply, especially since it contains the same active ingredients as the K9 Advantix II that earned our top recommendation. However, the performance is not on par, and we think you’re better off getting a product that works, instead of spending your money on an inferior imitation.

    • 5-way protection
    • Made some dogs sick
    • Only lasted a few days
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    8. Vet’s Best Flea & Tick Spot-on Drops

    Vets Best

    Like many people, we were attracted to the plant-based formula that Vet’s Best offers with its Spot-On flea and tick drops. Even better, it’s very affordably priced for the four-month supply that’s included. Of course, if it worked as well as advertised, it would have certainly worked its way up to a higher position on our list. In our experience, it just wasn’t effective at reducing the fleas and ticks on our furry friends. We tried it several times and in several locations with the same performance.

    Though it didn’t work for its intended use, it did make a nice yellow fur dye. We didn’t want that effect, and it took a while to wash out, so this is a drawback to be aware of if you have a canine with light-colored fur, especially white. Beyond the yellow staining, it’s also got a pretty offensive scent that we didn’t enjoy having stuck to our dogs. In the end, we don’t really suggest this product, even though we wanted to like it for the plant-based approach.

    • Plant-based formula
    • Had little to no effect on pests
    • Turned white fur yellow
    • Strong smell

    You may aso like: How to Keep Flies Away From Your Dog (6 Proven Methods)

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    9. Adams Plus Flea & Tick Spot On


    The best thing we can say about the Adams Plus flea and tick Spot-On drops is that they’re very affordable for any budget. Of course, they didn’t do what we hoped, so even though they’re very affordably priced for the three doses that you get in a package, we don’t think they’re one of the better values.

    They’re supposed to be fast working, but it was several days before we noticed any difference. After that, it was just a few more days before the fleas had come back with a vengeance, undoing any effect the Adams Plus drops had. Like many other drops we tested, these had a very strong and unpleasant odor that we’d rather stay away from. We’d suggest spending your money on something that’s proven to get rid of the pests that are plaguing your pup.

    • Priced very low
    • Took several days to see any effect
    • Pests came back in just a few days
    • Very strong odor
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    10. Solimo Flea & Tick Topical Treatment for Dogs


    One of the pricier options we tested, the Solimo flea and tick topical treatment was also one of the least effective ones. It’s got the same active ingredients as Frontline Plus, but in our testing, it didn’t show itself to be nearly as effective. In fact, we didn’t think it killed any of the pests that we were hoping to see die. We made several applications with the same results. Also, similar to many other products we tried, this left a strong odor on our dogs that we’d rather do without. If it had been effective, we could look past the price. As it is, we believe the Solimo flea and tick topical treatment is overpriced and ineffective, which is why it rounds out the bottom of our list.

    • Same active ingredients as Frontline Plus
    • Overpriced
    • Wasn’t effective at killing pests
    • The strong odor wasn’t pleasant
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    When you discover the beginnings of a pest infestation on your dog, you need to act fast with the right product before the problem explodes out of proportion. To help ensure you make the right decision, we’ve gone through the hard work of testing out all the options to find the most reliable and effective choice. You’ve read our reviews and you know how they stack up against each other, but before you make a purchase, we’re going to quickly summarize our top recommendations.

    Our number one choice that we think is the most effective is the Bayer K9 Advantix II flea prevention drops. A package contains enough to keep your dog protected for four months. Each dose kills the existing pests within 12 hours and continues to work for 30 days. In our testing, it was the most effective at actually killing the unwanted intruders. Our runner up and second choice is the Hartz Topical flea and tick prevention. This full-body protector was very affordable and still managed to be an effective remedy to our pest problem for a full 30 days from application.