Is a Flea Treatment with Chemicals Safe for My Cat? - Cat Info Detective

Is a Flea Treatment with Chemicals Safe for My Cat?

Skye Blake looking left through magnifying glass

Hey there, it’s Skye Blake, Cat Info Detective, here to let you know what I’ve found out about flea treatments with chemicals in them.

paw prints coming in from a distance

Am I a Bad Kitty Parent if I Use Chemical Flea Products Instead of “Natural”?

Chloe lounging on a chair

Of course not, as long as you’ve been responsible to figure out the best products for your situation.

If you haven’t already, check “Getting Rid of Fleas…For Cats Only!” to answer vital questions that will help you make a good decision.

But Aren’t Chemicals Dangerous For My Cat?

They can be dangerous if not carefully used, however, when properly diluted and applied, they can be effective against fleas and safe for your fluffy furball.

It Depends On…

Tabby & white cat looking surprised
  • what kind you use
  • how you use them
  • if you follow instructions carefully
  • how often they are applied
  • if they are a proper dosage for your cat’s weight rangeYour cat’s body doesn’t process things the same as people or dogs.  

But There Are So Many Products, How Do I Know Which to Use or What’s In Them?

So, the best way to keep you and your cat safe is KNOW WHAT YOU’RE USING and KNOW YOUR CAT!

First, check below to find out about various products to use for putting on your kitty. These are simply ways of applying different types of insecticides.

Second, learn about the three basic types of flea treatments: “chemical”, “natural” and “homemade”.

This page is about “chemical” types. You can find out more about “natural” and “homemade” on separate pages.

These Flea Treatment Groups Vary Greatly In…

various chemical flea treatments
  • types of ingredients
  • effectiveness
  • length of protection
  • control of other pests (lice, ticks, worms)
  • price
  • safety
  • ease of use

Review the options below to find out more about the traditional “chemical” types… what’s easiest to use, safest and most effective for your purpose.

Here’s a list for your convenience. I make no money from them.

Costs range from cheap ($) to expensive ($$$$): cheap = $ 0-10; average = $ 10-20; high = $ 20-30; expensive = $ 30+

Flea Collars

Orange Tabby Cat Scratching Herself

Traditional flea collars have one or more of the following chemicals in them as active ingredients:  Flumethrin, Imidacloprid, S-Methoprene, Tetrachlorvintos.

Some cats won’t wear them, especially with strong scents.

Others lose hair and/or get sores where the collar sits.

If your buddy goes outside, there are some break-away collars that come off if it gets stuck on a fence, tree branch, or other hazard.

Here are some examples…

Ginger cat wearing a flea collar
  • Seresto® 8-month Flea & Tick Collar – claims to have an innovative delivery system, killing fleas before they bite $$$$
  • Hartz® Ultra Plus® – 7-month Flea & Tick Collar – claims to work quickly and continue for 7 months $
  • Adams™ Plus Flea & Tick Collar for Cats – claims to work immediately and continue for 7 months $

FInd out more about Seresto and other flea collar alerts and controversies at “Cat Flea Collars

Sprays, Powders & Shampoos


Sprays, Powders & Shampoos have as active ingredients, one or more of the following:

Dioctyl Sodium Sulfosuccinate, Etofenprox, Fipronil, MGK 264 (N-Octylbicycloheptene Dicarboximide), Piperonyl Butoxide, Pyrethrins, Pyridine,  Pyriproxyfen, S-Methoprene, Undecylenic Acid.

If you’d like to know more about these ingredients, click here…

“Chemical” Sprays

Spray bottle

Flea sprays have insecticides and are used to help get rid of fleas and prevent their return.

They’re used now more in the home than directly on your cat.

This is because most kill only adult fleas, get your cat all wet, and other products are available that many people feel are easier to deal with for cats.

  • Adams™ Plus Flea & Tick Spray – claims to kill ticks, adult fleas, eggs and larvae and break the cycle for up to 2 months $$
  • Advantage® Flea & Tick Spray – claims to kill adult fleas, hatching fleas and eggs, ticks, and lice on cats over 7 months old; also used in the house $
  • Sentry® PurrScriptions® Plus Spray – claims to kill fleas, eggs and ticks; protects for up to 30 days on cats and kittens over 12 weeks $$

“Chemical” Shampoos

Sphynx cat after flea spray

Flea shampoos have insecticides added in dosages that will kill fleas while cleaning your kitty safely… that’s if you can give your cat a bath!

  • Advantage® Treatment Shampoo – unscented; claims to kill fleas and ticks on contact; use only on cats and kittens over 12 weeks old and not more than once a week $
  • Sentry® PurrScriptions® Plus Shampoo – claims to kill fleas, eggs and ticks; protects for up to 30 days on cats and kittens over 12 weeks $$


silver magnifying glass

There are some flea powders available but are mostly used on dogs and in the house (carpets and floors).

Powders are not recommended to use on cats since they’re messy (think clouds of baby powder), only effective while on the cat, rub off quickly and are swallowed during grooming.

Powder can also be licked off a dog if your kitty decides to groom her canine buddy!

It’s claimed that powders in large amounts can cause breathing problems in cats.

Topical Flea Treatments

veterinarian examining cat

Topical (directly on skin-usually between shoulders) have:

Dinotefuran, Etofenprox, Fipronil, Fluralaner, Imidacloprid, Indoxacarb, Moxidectin, Pyriproxyfen, Sarolaner, Selamectin, S-Methoprene, Spinetoram

A topical flea treatment is a pre-measured dose of insecticide applied to the skin (not just the fur) on the back of a cat’s neck, where they can’t lick it.

The dose is determined by weight of the cat.

Since they are pre-measured, they’re easy to apply either by you or your vet and usually last about a month.

cat scratching fleas

It’s claimed topical products don’t hurt a cat if put on the skin, but can be harmful if swallowed.

There are various scientific studies that show this to be the case, and also confirm that the most common cause of problems is people misusing the products.

Some examples of topical flea products are given below. They kill fleas for one or three months.

Cat waiting for topical flea treatment
  • Advantage® II Flea Treatment – claims: “Veterinarian-recommended treatment kills all life stages of fleas on kittens and cats 8 weeks or older”; begins working in 12 hours; use monthly on cats over 4 weeks old $$$
  • Frontline® Plus – claims to kill adult fleas, larvae and eggs for 30 days on cats over 8 weeks old $$$
  • Bravecto® Topical Solution – claims that one dose works for 3 months and kills fleas and prevents infestations in cats 6 months and older $$$
  • Revolution®Plus – claims it works against heartworm and fleas for one month (best to use only under the guidance of a veterinarian) $$$

Oral Flea Treatments

tabby cat in tub-yawning or angry

Oral treatments have nitenpyram or spinosad as active ingredients.

Check with your vet about using these to be sure they’re fine for your cat.

Oral flea treatments are medications given by mouth in liquid, pill or chewable tablet form.

They are useful for situations where you have concerns about young children or others in the household getting flea products on their skin or in their mouths.

Oral flea treatment

Here are some examples…

  • Comfortis® – chewable beef-flavored tablet; claims to kill fleas within 30 minutes; effective for one month. Use on cats over 14 weeks old $$$$
  • Capstar™ – claims to work within 30 minutes and is over 90% effective in killing adult fleas in hours. Use in cats and kittens weighing 2 to 25 pounds. Can give as often as once a day for infestations. $$$
cat yawning
  • Flea Away® Natural Flea, Tick & Mosquito Repellent for Dogs & Cats – liver tablets; claims it’s a …”safe mixtures of vitamins”…”works by actually covering up the smell of Co2, which is what attracts the fleas to bite.” Takes 30 days to start working; can be used in conjunction with other treatments. $$
  • Credelio™ Flea & Tick chewables for cats by Elanco™- these are tablets that contain lotilaner, a newer broad-spectrum insecticide. It’s claimed that cats accept it well, which makes it easy to use, and is very effective against both ticks and fleas.


lady & black cat

As a result of all my snooping into this topic, I’ve concluded a couple of things you might find helpful.

First, don’t be afraid of chemicals.

Second, respect that they’re helpful if used carefully, but dangerous if you don’t follow instructions well, so don’t be lazy or sloppy when you use them.

If you’d like to know about the chemicals in these flea products in more detail, check this out…

What Is a Flea? What Does It Look Like?How to Kill Fleas on Kittens, Senior & Sick Cats
Ways to Get Rid of Fleas on Healthy Cats!Getting Rid of Fleas…For Cats Only!
What Chemical Ingredients Are in Flea Products?What is a Natural Flea Treatment for My Cat?
Natural Flea Remedies You Can Buy Flea Control, the Homemade Way…
What Are Essential Oils…Do They Kill Fleas on Cats? What Is a Tick?
Cat Flea Collars


Sources used on this website are either primary or secondary.

Primary are always preferable and have the most reliable information because primary sources are original and directly referenced.

Scientific abstracts and data are good examples of primary sources.

Secondary sources are weaker because they usually consist of opinions or articles that give no sources of their own, however, sometimes they refer to primary sources.

Thus, when I use secondary sources most are those with some authority, such as veterinarian or cat behaviorist books and articles.

List of Sources

Some of these sources sell products. This list is for your convenience only. I make no money from it.

Chewy, Inc.: products and pricing

“Die Fleas! Die!…Freaky Cheap Flea Control”, by Paul Wheaton, Paul Wheaton Permaculture

“Elanco launches Credelio oral flea and tick control for cats”, Arlo Guthrie ,Veterinary News, VetSurgeon,org, 13 Nov 2018

“Flea Powder for Pets – How It Works and When to Use It”, by Jacob Olesen

“Fleas” by David J. Shetlar and Jennifer E. Andon, Ohio State University Extension, Department of Entomology, January 5, 2012, HYG208,

“How to Choose the Safest Flea Treatment for Your Cat”, by Jennifer Coates, DVM, PetMD

“How To Get Rid Of Fleas – 7 Natural Ways to Banish Fleas on Your Pets and in Your Home”, by admin,, February 13, 2015

“Insecticides”, Compendium of Pesticide Common Names

“Lotilaner – a novel formulation for cats provides systemic tick and flea control”, by Ian Wright, NCIB, PMC, US National Library of Medicine, National Institutes of Health

Petco®: products and pricing