How Long Does It Take for Flea Collar to Work? (Tips and FAQ)

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how long does it take for flea collar to work

Generally, chemical flea collars start to work in the first 24 hours, and the results should be noticeable within 3-4 weeks. As for natural flea collars, they take longer to deliver the results.

Each case can be different depending on various factors, which include: the types of ingredients used, the collar manufacturer, usage, hygiene, the stages of the flea infestation, and your dog’s condition.

Various Factors Affecting Flea Collar


The composition of the flea collar affects how long it takes to work.

Chemical flea collar uses active ingredients such as flumethrin, imidacloprid, and tetrachlorvinphos that work faster than natural ingredients. However, exposure to these active ingredients can result in symptoms that vary from mild to life-threatening.

Natural flea collar uses natural ingredients such as citronella oil, cinnamon oil, polyethylene, Eucalyptus oil, and so on. These ingredients take a bit longer to work and do not kill fleas only repel them, but they are safer for your dogs.


Best dog flea collar brands usually offer faster and better results than the cheap ones.


For maximum results, it is important to read the manufacturer’s instruction manual first before using the collar. For example, you might not know the flea collar that you buy is not waterproof. Accidentally exposing the collar to water can make the collar less effective.


To make the collar work faster, you need to keep your dog, and her environment cleans too. Some steps that you can take:

  • Clean your dog with flea soap or shampoo.
  • Replace your dog’s bedding to prevent re-infection.
  • And vacuum your floors regularly.

Stages of Flea Infestation

Most flea collars work best for the early stages of flea infestation. In case of a severe flea infestation, you need to combine the collar with other forms of flea treatment like tablets and spot-on treatments. Discuss with your vet to determine the best flea treatment methods for your dog.

Your Dog’s Condition

German shepherd with flea problem.

Dogs with a weaker immune system will take a longer time to heal up. To speed up the process, make sure to feed your dog healthy foods and supplements.

Other Flea Collar FAQs

How To Activate a Flea Collar?

Most flea collars require you to unroll and remove the plastic connectors on the inside of the collar to activate. Read the instruction manual to make sure.

How to Make a Natural Flea Collar?

Making your own natural dog flea collar at home is easy.

1. Get a soft nylon or cotton collar that you can buy at your local pet stores or online stores.

2. Then infuse the collar with the ingredients listed below.

  • 1 teaspoon of unflavored vodka.
  • 1 drop cedarwood essential oil.
  • 1 drop eucalyptus essential oil.
  • 1 drop lemongrass essential oil.

Mix all the ingredients to a small bowl, and stir to blend.

3. Soak the collar in the solution until fully absorbed, air dry until it’s semidry and you’re done.

Remember do not use this collar on dogs under one year old and never apply the ingredients directly to your dog’s fur.

How Tight Should a Flea Collar Be?

You can use the two-finger rules to determine how tight the dog flea collar should be. Once you have fastened your dog’s flea collar, you should be able to slide your pointer and middle fingers between the collar and neck, and the collar should feel snug but not tight.

What Flea Collar Works Best?

The answers can be different from dogs to dogs.

Which is Better Flea Collar or Drops?

Flea collars and flea drops have their own pros and cons because the answer is really up to you. The following is the list of pros and cons of each for your consideration.

Benefits of Flea Collars

  • Flea collars are convenient and easy to apply. You just need to put the collar on your dog, and you’re all set.
  • They are less expensive than other forms of flea treatment.
  • They provide longer protection. Many flea collars provide protection from fleas for up to 6 to 8 months.

The Downsides

  • Flea collars, notably the chemical ones, can be toxic to your children and dog.
  • Flea collars take longer to work compared to flea drops.
  • In case of severe flea infestations, you need to combine a flea collar with another treatment method.

Benefits of Flea Drops

  • Flea drops are fast-acting. In most cases, the results are noticeable within 30 minutes.
  • They are safe and are not harmful to people or children.
  • The medications help to get rid of other types of parasites as well, including different types of worm and mites.

The Downsides

  • Some dogs might experience adverse side effects such as upset stomachs, and vomiting.
  • Flea drops tend to be more expensive than flea collars.

What Are The Side Effects of a Flea Collar?

The residual toxins from chemical dog flea collars can be hazardous to both humans and dogs. The effects are ranging from skin irritation and chemical burns to seizures and organ failure.

How to Treat Flea Collar Burns on Dogs?

Minor flea collar burns can be treated with the following steps:

  1. Remove the flea collar immediately.
  2. Gently clean the burned area with a warm, wet towel. Dry the area completely.
  3. After the skin has dried, apply a small amount of witch hazel extract.
  4. After the witch hazel has been absorbed, continue applying coconut oil.
  5. Do this daily until your dog’s skin is healed.

When To Remove Flea and Tick Collar?

If there are no adverse side effects after you have put the collar on, you should wait for a couple of weeks, and if there is no improvement, you can remove the collar.

Another time is when your dog takes a flea and oral tablet, or a spot-on treatment, you should remove the flea collar when the day is done. Getting too many active ingredients can make your dog suffer negative effects.

What If a Pregnant Dog Wears a Flea Collar?

Any medication given to pregnant dogs can result in harm to the dam, birth defects to the puppies, or even spontaneous abortion.

If your pregnant dog suffers from flea infestation, it’s best to bring her to your vet to determine the best options.

Can My Dog Have a Flea Collar On When She is Nursing?

Flea collars are not recommended to be used on nursing dogs or puppies under the age of 7 weeks. For nursing dogs, you should only use approved flea treatments such as Frontline Plus and Revotuion.

What to do If Child Was Chewing on Flea and Tick Collar?

If your child was accidentally chewing on flea and tick collar, the first thing that you should do is to call the poison information center and ask for advice.

Tips: You should remove any extra length that the collar has to make it less attractive for your child.