Do Flea Collars Kill Fleas Already on Dogs?

Do flea collars kill fleas already on dogs?

Do flea collars kill fleas already on dogs? The short answer is yes.

Once it’s around your pooch’s neck, the flea collar will begin working. The chemicals in the flea collar will kill adult fleas, though some target juveniles too.

A flea collar, however, isn’t a one-size-fits-all solution to pest control.

Let’s have a look at how flea collars work, their benefits and drawbacks, and other methods of flea control.

What is a Flea Collar?

Flea collars are a form of doggie pest control. Like other chemical flea and parasite treatments, flea collars contain stuff that kills fleas, as well as prevent more of them invading your dog.

Flea collars have had a bad reputation in the past, primarily because they smelled terrible. Ingredients in the “flea collars of old” had a strong smell that killed and kept fleas at bay.

Modern flea collars are less smelly and slowly release their active ingredients. Eventually, the chemicals that kill and repel fleas will coat over your dog’s coat and protect them from an infestation.

Like other flea and parasite treatments, flea collars eventually require reapplication to ensure consistent protection.


Flea collars are convenient and (most importantly) effective. All you need to do is attach them around your dog’s neck, making them easy to use, and unlike topical flea treatments, there’s no drying period.

Many flea collars also last a long time, which means you can go longer without reapplication. Flea collars are especially useful if you’ve forgotten about reapplying your dog’s topical or tablet-based flea treatment more than once or if your dog spends a lot of time outside.

Their long-lasting effectiveness makes flea collars affordable too. Other flea treatments can get quite expensive, especially since most need reapplication every few weeks or monthly.


No treatment comes without risk, unfortunately. Flea collars are good for some, but they aren’t the ideal treatment method for every household and dog.

Though the majority of flea-killing treatment poisonings are from topical solutions, flea collars come with risks. The pesticides in flea collars can harm other animals in your household.

One chemical that can cause great harm is permethrin. Permethrin is toxic to cats. If you have both dogs and cats, you must avoid using flea treatments containing permethrin. If your cat shares bedding or likes playing with and grooming your dog treated with permethrin, they could get very sick.

Having constant contact with low-level concentrations of pesticides in flea collars and other flea treatments could harm people too. Small children are the most vulnerable to these risks, as they are still developing and tend to put everything in their mouths.

Scientists are still researching the effects of these products and chemicals on animals and humans. Government regulations also help protect people, animals, and the environment from treatments and chemicals that have been deemed too risky in comparison to their benefits.

Getting Rid of Fleas

Using a flea comb to find fleas on a dog

Treating fleas and other parasites is essential, and every veterinarian worth their salt will tell you that.

If you’re trying to get rid of fleas currently on your dog, using more than just a flea collar (or other chemical-based treatments) is important. Invest in a flea comb, which will help you pick fleas out of your dog’s fur individually.

Additionally, don’t forget to thoroughly clean the upholstery your home during a flea invasion with hot water. Like lice, fleas will live in fabrics and carpets, so ending the flea life cycle by getting rid of their eggs and larvae in your house will prevent a new infestation on your dog and other animals in your household.

Chemical flea treatments are essential and useful tools, but they aren’t the only way to get rid of fleas. Getting rid of fleas by using a combination of chemical treatments, flea combs, and regular cleaning will help reduce the chances of more fleas in the future.

Do Flea Collars Kill Fleas Already on Dogs?

Flea collars, like topical solutions, tablets, and special shampoos, are just another form of pest treatment in dogs. A flea collar is effective at not only repelling fleas but also killing any already on your dog. They are fast-acting, easy to use, and can last for longer than the average topical solution or pill.

However, they aren’t a miracle treatment. In recent years, there has been concerns over the safety of the active ingredients in flea collars and other treatments. We suggest speaking to your dog’s veterinarian about the most appropriate flea treatment for your family.

Regardless of how you manage fleas, chemical treatments aren’t the only thing you should do.

Flea combs are good for picking out the fleas already in your dog’s fur, and cleaning your upholstery, bedding, and carpets is crucial in ending the flea lifecycle in your house. Flea combs, proper cleaning, and treatments like flea collars work well together and will help you fight the battle against household fleas.