Are Flea Collars Safe for Dogs?

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Flea collars have been around forever and were one of the first flea products out there to help protect our dogs.

Because of how long collars have been used, many dog parents believe them to be a safe product.

Unfortunately, new data shows that isn’t entirely true.

However, it is also necessary to point out that not all flea collars are hazardous to your dog’s health. Some collars use less harmful pesticides with fewer side effects.

Whether a flea collar is the best choice for your dog, only you can decide, but it is critical to have all the information available when making an important decision of this nature.

Below we will share some of the data we’ve recently come across and break it down on whether flea collars are safe in various situations.

Are flea collars safe dangerous toxic chemical ingredients

What’s in Flea Collars?

Flea collars can have various active ingredients, and it depends on what brand you use as to what chemical is in the collar.

But the most common active ingredients seen in flea collars are:

  • Deltamethrin – Found in Adams Delta Force and Virbac Preventef-D
  • Amitraz – Found in Preventic Amitraz Tick Collar
  • S-Methoprene – Found in Hartz Ultraguard
  • Flumethrin – Found in Seresto
  • Imidacloprid – Found in Seresto
  • Propoxur – Was used in Bio Spot, Zodiac, Sergeant’s Dual Action, Scratex Color, and Sentry Dual Action.
  • Tetrachlorvinphos – Found in Seresto, Zodiac Flea & Tick Collar, and Hartz UltraGuard and poses a risk to children and adults.
  • Deltamethrin – Found in Adams Plus Flea & Tick Collar Plus, Salvo, and Sentry Dual Action Collar
  • Pyriproxyfen – Found in Adams Plus Flea & Tick Collar Plus

Of course, these are not the only chemicals found in flea collars, but these insecticides and pesticides are used in many popular brands.

Are Flea Collars Safe for Dogs?

Not all flea collars pose a health issue, but the reality is that recently dogs have fallen ill and even died after wearing flea collars containing two very potent pesticides:

Tetrachlorvinphos and propoxur.

Based on the latest Incident Summary Report for the EPA, more than 75,000 incident reports were filed involving the Seresto flea collar.

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Of those reported, almost 1,700 reports ended in the fatality of a pet.

And more than 10,000 cases were for moderate to major health issues1.

The Natural Resources Defense Council (NRDC) reported that many flea collars use organophosphate (OP) compounds which have proven to be dangerous to dogs and humans.

Reactions have occurred after prolonged use, but also when used for only one day2.

In 2009, the NRDC published a report outlining the dangers of using flea collars specifically containing tetrachlorvinphos and propoxur3.

The report stated that these two chemicals were the most dangerous pesticides still legally used in consumer products.

And as you can see above, these two insecticides are used in several flea collars.


Some flea collars may be safe, but you should avoid flea collars containing organophosphate compounds such as tetrachlorvinphos and propoxur.

Flea collar safety puppies pregnant senior old dogs

Are Flea Collars Safe for Puppies?

Although some flea collars state that they are safe to use on puppies, they still may not be the safest option.

If a puppy were able to get it off and chew on the flea collar, the pesticides in the collar could cause significant harm. 

Also, flea collars containing more potent chemicals may be more hazardous to young dogs.

Additionally, some vets feel flea collars are not the most effective flea preventative, so they often recommend topical or oral flea medications.


Flea collars are not the safest flea preventative, so you should consider other flea preventative options.

Are Flea Collars Safe for Pregnant Dogs?

Extra caution needs to be taken with pregnant dogs, and most flea collars state that they should not be used for female dogs who are expecting.

Additionally, this rule also applies to female dogs who are nursing.

It is vital that before you use a flea collar for your pregnant or nursing dog that you check with your veterinarian first.


 As a general rule. flea collars are not a safe option for pregnant dogs.

Are Flea Collars Safe for Older Dogs?

Much like puppies and pregnant dogs, seniors dogs may have more fragile systems, so greater care needs to be taken when using medications and flea preventatives.

Because my seniors had health issues, as many seniors do, my vet recommended I use Frontline as a flea preventative instead of a collar or oral medication.


Flea collars are not the safest option for senior dogs because they may be more sensitive to more potent pesticides.

Are Flea Collars Safe for Humans?

Residue from a flea collar is what helps to keep fleas away, but that same residue found on your dog’s coat can transfer to other things such as their dog bed, furniture, and even to the humans petting them4.

According to the NRDC and the EPA, the concentration of specific pesticides in the residue found on dogs wearing flea collars is high enough to cause serious health issues to dogs and humans5.

I think of it this way: If I were to use a pesticide outside, I wouldn’t want to come in direct contact with it.

And when people pet their dog near the flea collar or come in contact with a contaminated surface, we expose ourselves directly to those toxins.


No, flea collars are not safe to be used around humans.


It is vital to take in the newest data regarding the safety of flea collars.

Still, it is also important to remember that not every dog or human who comes in contact with a flea collar will experience an adverse effect.

As dog parent’s we must weigh the pros and cons of using flea prevention versus risking our dogs becoming infested with fleas.

The bottom line is that all flea treatments carry a potential risk; however, the severity of these risks vary.


Do Vets Recommend Flea Collars?

Some vets do, though many recommend alternative options that may be safer and more effective such as topical or oral treatments.

What Are the Side Effects of a Flea Collar?

Itching, redness, seizures, weakness, loss of control of bodily movement, high or low body temperature, lethargy, depression, diarrhea, urinary incontinence, low blood pressure, vomiting, difficulty breathing, loss of appetite, uncontrolled muscle spasms, and abnormal heart rhythm.

Are There Any Safe Flea Collars?

All flea collars run some risk of side effects, but I would say Vet’s Best Flea and Tick Collar would be a safe option.

Are Flea Collars Harmful to Humans?

Yes. The residue from flea collars can easily transfer to humans, and recent reports show that some have caused seizures, heart arrhythmia, fatigue, and ear, nose, and throat irritation.



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