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Toxic Chemicals Commonly Found in Flea and Tick Products

As a lover of the environment, GetFactsnotHype takes a special interest in protecting people and planet with wiser, eco-friendly choices.

This guide will help you identify and avoid three toxic chemicals that are commonly found in flea and tick products intended for pets.

This guide will help you identify and avoid three toxic chemicals that are commonly found in flea and tick products intended for pets.

3 Toxic Chemicals Commonly Found in Flea and Tick Products

  1. Amitraz
  2. Pennyroyal
  3. Pyrethrins (From Mums)

Below, you'll find a full description of each chemical and its possible effect on your dog.

Amitraz Is Toxic to Pets

Amitraz is a formamidine pesticide, acaricide, and insecticide, and its toxicity has been found mostly in cases in the country of Turkey; however, the USA is starting to see it being used more often both in agricultural products like livestock pest management and products for domesticated pets.

Children are particularly susceptible to amitraz poisoning more so than adults, and it can interfere with normal child development. Children often hug their pets, lay next to them, and crawl around on the floor close to where animals lay, so it is just as important to protect your child from this chemical as it is your pet.

Amitraz is also suspected to disrupt the endocrine system and may be a possible carcinogen even to adults, says the EPA (Environmental Protection Agency). The state of California has identified this as a developmental toxicant resulting in low birth weights, birth defects, and even problems that rear their ugly head as the child grows.

This has been used on dogs for mange as well as being in some solutions for flea and tick control, so the paw licking could possibly be a method of ingestion. More importantly, however, because dogs chew on just about everything, a collar with this chemical could be chewed on, thereby causing the toxicity. Even though this is not an approved chemical for cats, some pet owners have treated their cats, exposing them to this toxicity. Zema has some products containing amitraz.

More Toxins in Pet Products

More Toxins in Pet Products

Pennyroyal Is Harmful to Pets

I keep seeing this cropping up over and over on the internet as a flea and tick remedy, particularly in shampoos, and yes, it might be effective, but pennyroyal is not safe for cats and dogs.

Pennyroyal is known by many names, including squawmint, pudding grass, stinking balm, and Mentha pulegium. Pennyroyal oil can cause liver and kidney damage, hemorrhaging of internal organs, coughing up blood, seizures, coma, and death.

Additionally, the U.S. Food and Drug Administration (FDA) has not evaluated this for purity, safety, or effectiveness and no regulated manufacturing standards are in place. Blood tests, however, have revealed elevated liver enzymes, anemia, and prolonged clotting times.

It is the active poison "pulegone" in the oil that is toxic to the liver causing this damage. It is not safe for dogs to ingest (through paw licking), but there has been a case of toxicity with dermal application as well. This is a real no-no for cats who would ingest by bathing all over.

Pyrethrins From Mums Are Toxic

This class of chemical also includes the pyrethroids family of synthetic pyrethins, such as permethrin, bifenthrin, and cypermethrin. Derived from chrysanthemum flowers (technically Chrysanthemum cinerariifolium) and being biodegradable, it seemed to have promise, but now pyrethrins are a concern, reports NBC news channel 4 in Southern California. It was hoped to replace the bad organophosphates but instead has caused serious problems.

In one case, a woman saw her dog get sick within hours of topical exposure, and within three months, it was dead. Of course, part of this problem is that there are concentrations anywhere between 40 percent and 85 percent solutions, and really, you don't have to be fatal to insects in order to get the insect repellent effect. Additionally, there has been a case of a severe asthma attack by a child after being around an animal treated with pyrethrins.

Other symptoms for dogs and cats range from mild, including hair loss and drooling, to mid-range issues such as tremors, seizures, profuse salivation, and hyperexcitability. Cats are particularly at risk because they have less-efficient metabolic pathways and, therefore, can have shock, hypothermia, and even death within a few hours of toxicity if not treated. Etofenprox, d-phenothrin, cyphenothrin, and deltamethrin (or decamethrin) are other names of pyrethrins and pyrethroids to watch when reading your labels. You can see more on pyrethrins at The Veterinary Journal Volume 182, Issue 1, October 2009, Pages 7-20.

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Pyrethrins can be made from mums

Pyrethrins can be made from mums

Laws and Lawsuits on Pet Products

The U.S. Environmental Protection Agency (EPA) is notorious for approving pet products first and asking questions second, only to yank the product from the shelves at a later date. They have done this with chlorpyrifos products, cancelled in 2001; diazinon products, jerked from product shelves in 2001; and phosmet products, stopped for pet use by 2004.

This government agency does not require extensive testing and when they do test it is usually only for one breed and usually only after complaints on a product. In November of 2001, a Ms. Van Wyk of Rhode Island filed a lawsuit for a cat product that was a common problem for adverse conditions. She also claimed Hartz knew about the problem of their "Mountain Corp Advanced Care Once a Month Flea & Tick Drops for Cats" since earlier in March of that year, but still continued to sell it anyhow.

The product contained the pyrethroid d-phenothrin in spot on treatment form, but the suit was ultimately dropped perhaps because she settled out of court. Now the EPA does continue to monitor products with the classification of pyrethrins and since that time has supposedly written a piece in BMC Genomics, a peer-reviewed online journal with regards to causative effect of neurological functions on rats treated with pyrethrins, although I was not able to locate it.

But how does this kind of thing slip by in the first place? That's because the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) does not require field trials of pet products prior to approval like the testing of products for humans. Previously FIFRA was called the Federal Insecticide Act of 1910 and has undergone many changes since then including major revisions in 1972, but it could still use improvement.

Which Companies Produce Toxic Pet Products

Hartz flea and tick products have gotten a lot of bad press about the chemicals they use, but they are not the only offenders. Pyrethrins, permethrin and pyrethroids have shown up in some of the products made by: Sergeants; Sentry; K9 Advantix; Bio Spot; Bio-Groom, and others. Additionally, there are several companies offering pet shampoo containing pennyroyal.

Frontline is one of the more well-known products and also more expensive in the line of flea and tick remedies, but with mixed reviews. Some sources say that Frontline's fipronil less readily binds with mammalian nervous system receptors and is only considered a possible human carcinogen and therefore has made the EcoWise Certified IPM Program Materials List.

However, Frontline's competitor, Hartz states that while Frontline's chemicals have a lower percentage of concentration of their active ingredient fipronil than Hartz's pyrethrins, it's still Frontline that is considered to be moderately toxic and they use the EPA's words to back their claims.

Hartz agrees that their own spot on treatment for dogs containing pyrethroid d-phenothrin and the pyrethroid etofenprox for cats (at 55% concentration) have higher percentages of active ingredients than Frontline but still causes less damage, and the EPA has in the past listed Hartz as less toxic than Frontline for that reason.

There could possibly be some truth to that, whereas 5 mg or 5 ml of one chemical is not necessarily less damaging than 10 mg or ml of another, because each drug has its own properties and reacts differently and in different breeds. If Frontline is right, then explain why some humans can take Excedrin or Tylenol for a headache, while others take Advil or Bayer, because the former at no concentration works at all for them.

How to Educate Yourself on Pet Product Safety

While I think the EcoWise list is a good place to start, I still think you need to keep educating yourself on new articles and pay attention to how your pet responds to the product. Additionally, the EPA has made numerous mistakes and damaging blunders before on just about EVERYTHING, so I'm more inclined to believe EcoWise. Another thing you can do is educate yourself with information, like a previous article I wrote titled "Avoid Two Chemicals in Flea and Tick Products."

Also, The Bio-Integral Resource Center (BIRC), known as (IPM) Integrated Pest Management Specialists have made available a 48-page manual you may order in hard copy as well as viewing an online version. You may obtain that 2015 Directory of Least-Toxic Pest Control Products here at the BIRC website.

If you suspect your pet may have chemical toxicity or even a lesser adverse reaction, please consult this website helpline for symptoms and what to do next. It is the Animal Poison Control Center, which is open 24 hours a day and available to the United States, Canada, and the Caribbean.


Repelling is one issue, but sometimes your pet may have a severe problem, or you are dealing with an infestation and need a chemical intervention. In that case, look for products with a lower risk, such as those containing the active ingredient: Lufenuron; Pyriproxyfen; S-Methoprene; Nitenpyram; or Spinosad.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2015 GetFactsnotHype

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