Flea Collar for Cats: Does It Make Them Lethargic?

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Written By Editorial Staff
Reviewed By Matt Cook

Veterinary Experts

Do you have a cat that is constantly scratching and licking itself? If so, it may be because your furry friend has fleas.

Fleas can be a nuisance for both cats and humans alike, but thankfully there are ways to get rid of them.

Flea treatments for cats come in various forms, including collars, drops, powders, and shampoos. Some people are concerned that using flea treatments may make their cat lethargic.

However, research has shown that this is not usually the case.

While you should always speak with your veterinarian about the best flea treatment for your cat, collars are generally safe to use.

They usually work by releasing a small amount of pesticides over time to kill any fleas on contact. Some even repel ticks too!

This can keep both pets and humans from getting bitten or stung by these pesky critters.

If you are worried about your cat becoming lethargic after using a flea collar, speak with your veterinarian. They will help you choose the best treatment for your pet.

And remember, just because a flea collar may make your cat a little drowsy, it does not mean that it is not working!

Most cats will get used to the collar after a few days and return to their usual selves. So don’t hesitate to try one out if your cat is struggling with fleas. They may be the solution you are looking for!

Thankfully there are many high-quality flea collars for cats in the market nowadays. So be sure to do your research and find the perfect collar for your furry friend!

What is a flea collar for cats, and how does it work?

A flea collar is a flea treatment that your cat wears around its neck. It works by releasing a small amount of pesticides over time to kill any fleas on contact and even repel ticks!

It is one of the most popular flea treatments for cats. It is easy to use, affordable, and generally safe and effective.

Side effects

Flea collars are generally safe to use and do not have any significant side effects.

However, you should always speak with your veterinarian about flea treatments before using them on your pet.

This is especially true for cats because they can be sensitive to flea medications.

Some flea collars may make your cat lethargic, but this is not usually the case.

After a few days, most cats will become acclimatized to the flea collar and resume their usual activities.

The United States Environment Protection Agency (EPA) lists the following as side-effects of using flea collar on cats or dogs:

  • Skin Irritation and redness
  • Vomiting
  • Diarrhea
  • Trembling
  • Depressed appearance
  • Seizures

If you have concerns about your pet having an adverse response to a flea and tick medicine, look at the precautionary statement on the label and contact your veterinarian right away.

Bathe your pet with mild soap and a lot of water in addition. If your cat shows any adverse reactions after wearing a flea and tick collar, remove it and discontinue use.

Many vets feel that using a counterfeit product is the main reason of the side effects caused by flea collars.

“There are apparently a lot of counterfeit collars out there that people order online and that either have no effect or are potentially very toxic, says Dr. Adriano Vatta who is an associate professor of parasitology at the Louisiana State University School of Veterinary Medicine and secretary-treasurer of the American Association of Veterinary Parasitologists.

He referred to the concerns about skin irritation in cats using Seresto collars.

How to use flea collars for cats?

Place the flea collar around your cat’s neck and adjust it so that it is snug, but not too tight.

You should be able to fit two fingers between the collar and your pet’s skin comfortably.

Most flea collars will last for around six to eight months. However, it is important to check the label of your specific collar to be sure.

It is also a good idea to replace the flea collar every time you switch flea treatments, just to be safe.

If you are unsure about using flea collars correctly, speak with your veterinarian or ask for help at the pet store when you buy one.

When should flea collars be used?

Flea collars can be used year-round and do not need to be switched out during different seasons.

However, it is always a good idea to speak with your veterinarian about flea and tick treatments, as they may have specific recommendations for your area.


Flea collars offer a variety of benefits, including:

  • Ease of use: they are easy to put on and take off
  • Affordable flea treatment: they are a very affordable option, especially since they do not need to be replaced as often as other flea treatments.
  • Long-lasting flea and tick control: most collars last for around eight months and provide long-lasting flea and tick control.
  • Convenient: they are a very convenient flea treatment option, as they do not require any special application.


The main drawback of flea collars is that some cats may experience skin irritation or lethargy after wearing them due to pesticide sensitivity.


Flea collars are very effective at preventing fleas from biting your cat.

Speak with your veterinarian about flea treatments before using them on your pet because cats can be sensitive to flea medications.

Do flea collars make cats lethargic or tired and can this lead to other health problems?

Flea collars are generally safe flea treatments for cats. However, you must also consider the various flea collar strengths available on the market, which means verifying the packaging and information sheet that came with your cat’s particular flea collar is necessary.

This will help you determine whether using the treatment has any negative effects, and stronger flea collars do have a greater chance of making your cat lethargic or tired.

Speak to your vet about the side effects if you notice any.

What are some of the best flea collars for cats on the market today?

Some of the best flea collars for cats include:

  • Hartz UltraGuard Flea & Tick Collar for Cats
  • Adams Plus Flea & Tick Collar for Cats
  • Vet’s Best Flea and Tick Repellent Collar for Cats
  • Bayer Animal Health Seresto Flea & Tick Collar for Cats
  • PetArmor Plus for Cats, Flea & Tick Prevention for Cats
  • Sobaken Flea and Tick Prevention for Cats
  • Missona Flea Collar for Cats and Kittens
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