Are Flea Collars Safe For Cats?

When I was looking at different flea collars for my cats, I started wondering how safe flea collars really were.  Everyone close to me knows that I like to spoil my cats, and I’d hate to use a product that would hurt them.  So, I checked into the safety of flea collars to find out if they’re a good idea for fighting fleas and found some things that scared me.

So here’s the moment of truth, are flea collars safe for cats?  There are flea collars that are composed of a natural base and safe approach that poses little risk of serious side effects to your cat.  But the majority of over-the-counter flea collars rely on chemical compounds that can be toxic for cats. 

The safety of a flea collar depends on many factors, including correct usage, the cat’s allergies, and active ingredients. 

With that said…

Fleas are a serious problem that can cause issues on their own!  

White cat playing with a ball in the garden with a flea collars

So how exactly do you weigh the good intentions of flea collars with the risks?

In my opinion, it’s important to consider what’s actually at stake when you place a flea collar on your cat.  

Some of the dangers, whether incorrect usage of the collar or a skin reaction triggered by harmful ingredients, can be fatal.

If you do decide to get a flea collar, knowing the risks can help you find the safest option for your cat.

What Are The Safety Risks For Cats With Flea Collars?

It turns out, there are many safety risks posed for cats wearing flea collars.

Including some that I would’ve never considered before doing my research.  

While these devices are supposed to help combat pesky fleas, they can actually be dangerous for a wide variety of reasons.

First off, flea collars are worn around the neck, and once they’re secured, they’re pretty tricky to slip out of.  

This poses a surprising danger for curious cats that tend to explore.

Flea collars can get caught on objects, like fence posts and tree branches, quite easily.  

When a flea collar gets caught and the cat is unable to reach anything, it can result in an accidental hanging. Outdoor cats who are likely to climb trees and explore without supervision are at a greater risk for accidentally hanging themselves.

It’s also important that the flea collar is applied correctly.  

Fasten the flea collar carefully in accordance with the specific directions provided with the collar.  

Also, be sure that your feline meets the requirements necessary for the safe application of a flea collar, including age, weight and general health.  

These elements can play a big role in the safety risks to be expected when using a flea collar on your cat.

Cat Flea Collar Side Effects

Another problem that can pop up with the use of a flea collar is an allergic reaction.  

Depending on your cat’s unique skin sensitivities, it may react badly to a particular ingredient used in the flea collar you’ve chosen.  

Sometimes this can be tricky to determine in advance, because flea collars have multiple ingredients, and your cat may only be allergic to one component.  

Cats with skin sensitivities may experience scratching and biting around the head and neck area, in addition to redness and inflammation of the skin.  

Here’s Onyx’s sad story of using Sergeants flea collar: Although it’s not 100% that it was the collar:


In some cases, hair loss near the site of the collar can also be a result of an allergic reaction triggered by it.

One of the scarier and potentially more dangerous safety risks involved with flea collars relies on the ingredients used to fight fleas.  

Many over-the-counter flea collars depend on chemical treatments to kill and deter fleas.

Some of these chemicals have been deemed toxic for cats who are chronically exposed to them.  

In other words:

  • they can essentially poison your cat
  • cause cancer
  • stunted brain development
  • organ failure.

The chemical agents that have been linked with some of these severe health risks are:

  • Diazinon
  • Flumethrin (found in the Seresto collars)
  • Propoxur
  • Tetrachlorvinphos (TCVP)

So far experts have not yet concluded exactly how much exposure is necessary for these chemicals to create harmful health effects.  

However, they have found that treatment residue can remain on a cat’s fur for several weeks after a flea collar has been removed, providing prolonged exposure to the chemicals.  

So in the meantime, it’s probably better to be aware that you’re submitting your cat to this exposure risk, whether a flea collar is used once or repeatedly.

Finally, flea collars run the risk of poisoning your cat as a result of accidental ingestion.  

You probably know the saying, “Curiosity killed the cat…”

Well, in the case of chewing on, licking or eating a flea collar that has become unfastened, the risk of physical harm is quite significant…

Either by choking or poisoning.

Chemical Ingredients That Affect The Safety Of Flea Collars

If you’re still set on getting a flea collar for your cat, there are ways to evaluate the safety of each collar you’re considering.  

Flea collars can consist of a wide spectrum of different active ingredients.

Not all flea collars use the same formula for fighting fleas, so it’s important to check out the combination of chemicals used in the flea collar treatment.  Depending on the chemicals included, the overall toxicity and safety of the flea collar can be influenced.

You definitely want to watch out for collars that use organophosphate (OP) compounds.  

They may decrease the safety of the flea collar by including harmful chemicals.

These compounds are also known as phosphate esters, and they are typically considered toxic to small animals, like cats.  Traditionally, OP compounds have been used in a range of bio-targeted products, including nerve agents, insecticides, and herbicides.

Many over-the-counter flea collars rely on the use of OP compounds to effectively kill fleas.  

Both diazinon and tetrachlorvinphos (TCVP) are considered to be OP compounds.

Therefore, if the flea collar contains either of these chemicals, it places your cat at an increased risk of experiencing harmful health issues linked to poisoning.

Another consideration relevant to your cat’s health is the combination of medicinal treatments being used at the same time.  

Sometimes the risk of harmful reactions can be increased when a combination of different chemicals are used simultaneously.

To put it another way, particular chemical compounds can stir up dangerously when they come into contact with other potent chemicals.  

This can increase your cat’s chance of having a negative reaction.

This video below is about Billy and using the Seresto flea collar:


Take for instance the Seresto flea collar.

I read through the reviews from Amazon and several people stated their cats had some severe reactions like chemical burns around the neck.

I’ve read through this forum here where several cats were experiencing coughing, eye irritations, easily out of breath, vomiting, difficulty eating or walking.

This forum here stated her 2 cats were poisoned. One who could walk properly for months.

Also, note this warning for the Seresto collar:

Keep out of the reach and sight of children. Keep the collar in the outer packaging until use. As with any veterinary medicinal product, do not allow small children to play with the collar, or to put it into their mouths. Pets wearing the collar should not be allowed to sleep in the same bed as their owners, especially children. People with known sensitivity to the ingredients of the collar should avoid contact with the collar. Immediately dispose of any remnants or cut-offs of the collar. Wash hands with cold water after fitting the collar.

This is something I don’t personally recommend for cats.

This is one of the big reasons why it’s not recommended for a cat to be taking more than one oral flea repellent at a time.  

Always check with your veterinarian when introducing a new, medicinal treatment for your cat, such as a flea collar.  

Consider how the ingredients of the treatment may interact with other medicines your cat is currently taking.

Are Flea Collars Good For Cats?

But let’s get back to the whole reason flea collars were invented in the first place:

Fighting fleas!  

Do they kill fleas, yes they do.

But do you want to risk the side effects or hurting you cat with chemicals?

For me, no.

Also, know, I’m sure there are people out there that use these collars without any side effects to their cats. Which is great, but know what can and has happened.

That choice is yours.

We all know that fleas are a huge nuisance.

First of all, the cat flea, whose scientific name is Ctenocephalides felis, can transmit disease.  This pesky creature can also transmit parasites.  

Both of these issues can cause big health problems for your little feline, so you might want to try using a spot on, or a flea collar, to stop the flea in its tracks.  

Plus, fleas can carry these germs into your home, which makes snuggling up with your cat somewhat off-putting!

I think people continuously use flea collars because it’s just easy.  

calico cat on concrete wall with red flea collar

Picking up a flea collar at the store can sometimes be easier than scheduling an appointment and hauling the cat in the car to the vet.

There are a plethora of options on the cat market, many of which can be purchased as over-the-counter solutions, without a prescription.  

Plus, flea collars are somewhat affordable.  

Special oral medications and prescription pills aimed at fighting fleas can cost an arm and a leg.  

Flea collars, on the other hand, come with a full spectrum of price tags, making them a thriftier flea-fighting solution, in many cases.

Flea collars were developed to target flea infestations and prevent them from occurring in your cat’s fur.  

When you consider all the benefits of flea collars, it’s no surprise that they are one of the most popular methods for flea control.

Just know, it’s your choice at this point to take that risk.

[Read more: How to get rid of fleas in the house and your cats]

Safest Flea Treatment For Cats

After learning all the ins and outs of flea collars, I decided that if I was going to get one for my cat, I’d be sure to pick one that was a healthier choice than others.  

When you weigh all the risks involved with flea collars, it does become possible to distinguish which options are safer for your cat.

Here are a few tips to help you sort through your selection.

The first thing you want to do is take a close look at all the active ingredients included in the flea collars you’re considering.  

Remember, if any of these collars have the organophosphate compounds mentioned earlier, compare the dosages to see if there is one with a smaller amount.  

This may be a safer option than flea collars with a heavy percentage of organophosphate compounds in their treatment base.

Natural Flea Collar For Cats

Secondly, consider opting for a flea collar that features an herbal treatment.

You can try the Only Natural Pet flea collar that is safe for both dogs and cats.

Each non-pesticide collar contains:

  • oil of pennyroyal
  • eucalyptus
  • cedarwood
  • citronella
  • rue for protection that lasts up to 3 months  

Instead of using chemicals, herbal collars combine a variety of natural ingredients including:

  • rosemary
  • citronella
  • eucalyptus
  • pennyroyal
  • cedarwood

Flea collars with a natural base such as these are often a much safer alternative to chemically-treated collars.

For the DIY readers out there, check into making your own flea collar at home.  

There are lots of how-to recipes online, like this one here. 

Some home remedies for fleas include the use of lemons to create a natural repellent.

Homemade flea collars are not as complicated as they sound, and they give you the security of knowing exactly what ingredients you are exposing your cat too.  

If reading through the different ingredients of commercial flea collars sounds like a challenge you’re not up for, then creating your own flea collar may be a safer choice.

Related Questions

How do flea collars work?  

Flea collars are designed for one or both of these two functions: repellent and treatment.  Placed around the animal’s neck, the flea collar is treated with active ingredients, emitting a targeted medication that seeps into the animal’s skin or through the release of gas.  Depending on the active compounds of the medication, the product either repels fleas to prevent future flea infestation or kills fleas to address an existing flea infestation.

Is there a flea pill for cats?  

There are a number of flea pills for cats that are available either with a prescription or over the counter.  These medications are designed to be taken orally. Some flea pills for cats are designed solely for the treatment of existing flea infestations, while others are preventative.

How old does a kitten have to be to wear a flea collar?  

A kitten must be at least 12 weeks old before wearing a flea collar.  This is based on the general physical development that is required before a kitten’s body is able to support wearing a flea collar correctly.  

If you suspect that the kitten is underdeveloped or has not reached a typical size at 12 weeks, consult your veterinarian before fitting the kitten with a flea collar.

[Read more: Treating Kittens For Fleas]

Do flea collars work for cats?

Flea collars for a cat are fairly effective at repelling or killing fleas but it only works best as a preventative measure. The collar secretes this insecticide that sinks into your cat’s skin that may kill or repel fleas.

Flea collar vs drops for cats.  

A flea collar is used to repel fleas and kill them altogether.  These collars release a toxic gas to kill or prevent fleas from going on your cat. Drops for cats, or called a spot on, normally contain an insecticide that is used to kill adult fleas on contact.

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