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Natural Canine Health Symposium

The Dangers Of Flea And Tick Products

brown dogAs a veterinarian, I’ve been taught that the majority of flea and tick products are harmless and safe, but evidence now shows that both the ‘active’ and some ‘inactive’ ingredients in the spot- on preparations have been linked to serious health effects both in laboratory animals and in pets.

The Washington-based Center for Public Integrity (CPI), a nonprofit investigative news organization, and the National Resources Defence Council, an environmental advocacy group, have both published reports about the safety of prescription and over-the-counter flea and tick treatments.

Dr. Dobozy of the EPA’s Pesticide Division has found that the active ingredient (fipronil) in Frontine remains in a pet’s system with the potential for nervous system and thyroid toxicity. Tests on laboratory animals resulted in thyroid cancer and altered thyroid hormones, liver and kidney toxicity, reduced fertility and convulsions. Frontline’s web site creates the impression that the product stays in the oil glands of the skin. But Dr. Dobozy’s study showed that, in fact, it does enter the body and the organ systems.


Advantage contains the active ingredient Imidacloprid. In laboratory studies Imidacoprid has been found to increase cholesterol levels in dogs, cause thyroid lesions, create liver toxicity, and has the potential for damaging the liver, heart, lungs, spleen, adrenals, brain, and gonads. As a neurotoxin, it can cause incoordination along with labored breathing and muscle weakness. When this drug was tested after its introduction in 1994, researchers found an increase in the frequency of birth defects when it was tested on rats, mice and dogs.

In the Journal of Pesticide Reform, author Caroline Cox exposes thyroid lesions as a result of exposure to imidacloprid. Most people think that the pyrethrins (naturally occurring compounds from the chrysanthemum plant) and pyrethroids (the synthetic counterpart) are less hazardous than other tick and flea preventive ingredients. Data from pyrethroid-based insecticides was recently made public through the Freedom of Information Act and analyzed by CPI. According to CPI, from 2002 through 2007, at least 1,600 pet deaths related to spot-on treatments with the above mentioned ingredients were reported to the EPA. That was nearly double the reported fatalities linked to flea treatments without pyrethroids.


The pyrethroid spot-ons also accounted for more than half of the “major” pesticide pet reactions including brain damage, heart attacks and seizures. Non-pyrethroid spot-on treatments accounted for about 6 % of all major incidents. Bio Spot Flea and Tick Control, Defend EXspot Treatment and Zodiac FleaTrol Spot On all contain either or both of the active ingredients Permethrin and/or Pyriproxyfen.

Permethrin has been implicated as a carcinogenic insecticide causing lung cancer and liver tumors in laboratory animals. There is also a suspicion that it disrupts endocrine function. It can act as a neurotoxin, causing tremors as well as increased aggressive behavior and learning problems. Vectra #D, the new guy on the block, contains 36.08% Permethrins.

As a result of all this newly revealed information in the CPI’s report, the EPA in April 2009 announced it was taking a closer look at all spot-on flea and tick products. The EPA is also taking action to address uncertainties about the so-called ‘inert’ ingredients present in these products.

Safe alternatives are very much needed for flea and tick control. Medical problems that have become common in our dogs and cats could potentially be linked to these previously “believed to be innocuous” spot-on products.

The Best Alternative To Flea And Tick Products

The best solution for fleas, ticks and other parasites is prevention. Healthy animals aren’t good hosts for parasites. This means that once you expose your animal to toxic chemicals, including vaccines, drugs and flea and tick products, his liver and immune system are compromised, making him more likely to host parasites once those flea and tick products wear off. This spirals downward into a cycle of repeated applications and declining health.

“Healthy animals are less attractive, for reasons that science has yet to determine, to fleas and other external and internal pests and parasites, whose whole existence is one of opportunistic survival and multiplication” says Dr Michael Fox DVM. “Dogs and cats on the kind of ‘junk’ foods that are still widely sold are far more prone to fleas and other parasitic and infectious health problems than those who are on a wholesome, whole-food diet, ideally organically certified and of course nutritionally complete.”



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  • 16 Responses to The Dangers Of Flea And Tick Products

    1. Thank you for this valuable post.

    2. Marita Garza

      Please send me the recipe for flea and tick prevention that I can make. Tks

    3. liz barnard

      I am horrified to hear your sad stories about your doggies. My golden lasted to 16 with annual vaccinations to the age of 10, regular Frontline applications to cope with ticks and fleas and food out of a sack! Guess I can’t have done much wrong, his breeder said he lived three years lomger than any other of her progeny.

      • Dogs Naturally Magazine

        Good genetics can account for a lot. Many people smoke for most of their lives and live to 80 or 90 – but that only means they gambled and won, it doesn’t mean that smoking is good for them. It comes down to playing the odds and stacking the odds in your favor. The more toxins your dog is exposed to, the more you are gambling with his life.

    4. What natural products have you guys had success with, mainly with ticks? I have been using an amberstone collar on my dog with pretty good success (www.amberstonepets.com) and I also use the natural flea and tick spray by Quantum Herbals. Just curious what has been working for other people.

      • Dogs Naturally Magazine

        Our response is that healthy dogs don’t harbor ticks or tick borne disease. As always, build up a healthy immune system by feeding a high quality diet and avoiding drugs, chemicals and toxins and focus on creating health instead of preventing disease.

        • Botanica37

          That is not a good advice. Healthy animals do get bitten by ticks and do get TBDs, even when raw fed species appropriate diet and vax free. It truly depends on the area the dog is in and the exposure. A healthy dog, confined to a fenced back yard will have a lot less exposure than a dog walked daily in the woods. If the area in question is endemic for Lyme and other TBDs, every precaution should be taken for both dogs and humans to minimize exposure. People need to evaluate their specific circumstances and giving a generic advice like that does more harm than good.

          • Dogs Naturally Magazine

            Dr Ronald Shultz, noted vaccine researcher, lives in a Lyme endemic area and doesn’t vaccinate his dogs for Lyme.

    5. Lucy Hodge-Corrigan

      I meant to say Bleu will be gone TWO years on March 8th, to massive Kidney Failure, rather than the year and a half as I stated above…and Laci died six months later of cancer…

    6. Lucy Hodge-Corrigan

      I absolutely REFUSE to put that garbage into my current dog’s systems….I had two dogs that died a year and a half ago…my darling Sheltie, within three days…from kidney failure…and my Golden, six months later, to tumors and cancer.

      After giving Laci, the Golden, Heartworm and Flea and Tick medication, she began having seizures….BAD ones…not that there ARE any ‘good’ ones, but her’s were LONG seizures. One day, when I was applying the liquid to the back of her neck, as directed, it rolled off onto the floor. I live in a Heritage B&B…92 YEARS old…..with PURE Hardwood floors….and I watched in HORROR as this crap burnt through EVERY layer of varnish on there until it reached bare hardwood…and I vowed then…NEVER again….but it was too late….she died six months later, at the age of EIGHT, after suffering those seizures for YEAR’S….and my Vet would tell me it was nothing to worry about….

      My Sheltie, whose fur was thicker, didn’t have the stuff roll off HER fur onto the floors, but I never gave it to them again, and REFUSE to give it to my blind dog that I adopted and her little buddy LuLu….

      And Baby Bleu, my Sheltie will be gone three years now on March 8th, after seeming SO healthy, until I noticed she was so lethargic…and her kidney readings were almost in the 900′s, instead of the mid 50′s to mid 60′s, as is normal. And she was SEVEN! And six months later, Laci was also gone, so I lost both my ‘babies’ in SIX months, and I’ll FOREVER blame that trash on them dying!

      They were BOTH fed top of the line food….they were adored and cared for….and my heart is STILL broken….but I will NEVER put that garbage into another dog as long as I live. And thank you for the ‘recipe’ for the Flea and Tick stuff we can make ourselves….the Vet’s say it’s a major problem around here, as we seldom have cold winters like we did….I now live in Newfoundland, Canada, my home Province….so I totally appreciate finding another alternative and I want to thank you…for saving NUMEROUS dog’s lives by being HONEST and TRUTHFUL…a rare quality these days, when most Vet’s ‘peddle’ garbage sold to them by vendors and then convince ‘us’ to give it to our beloved pets!

    7. UrbanCollieChick

      Do you have cittions avaiable for Dr. Dobozy’s statement, and also for what you found in The Journal of Pesticide Reform? Thanks.

    8. Joann knoss

      Thank you


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