Flea and tick control is an important part of keeping your pet healthy, but are flea control products safe? The sad answer is… not really. Most flea and tick control products contain toxins that can cause vomiting and diarrhea, cancer, seizures and many more unfavorable side effects. The good news is, there are safe ways to prevent fleas, and keep your pet flea-free without harming them or your family.

Take a moment, and read the ingredients label on your pet’s flea control. You may want to have a seat, because the list can be dizzying. Whether you’re using an oral or topical commercial product, the chances are good that it contains a chemical that can potentially make your pet sick, or even harm you or your family.

Your Family’s Risk

Topical flea control products are most dangerous when it comes to cross-contamination. Young children are especially at risk. They just love to pet and hug their furry friends, and can easily forget that they are not to touch or pet Fluffy after her Advantage is applied. Even after several hours, the mixture is still very much saturated in the animal’s fur and skin, and can be transferred and absorbed through simple physical contact.

Orally ingested products aren’t much safer. While there is less risk for immediate contact, chemicals still have to go through your pet’s stomach, liver and other vital organs to get to their skin. At this point, the toxins can still be passed to human family members through physical contact.

What’s in the box?

The list of harmful chemicals and toxins in flea and tick control products is a long one. There are a few big ones, though, that contribute to a good majority of reactions or illnesses.


Imidacloprid is one chemical found in many pest preventatives, and over 400 household products. According to The Natural Resources Defense Council, this chemical has been linked to some cancers, and even reproductive issues in lab mice. K9 Advantix II and Advantage II are two of the most popular products that contain imidacloprid.


Fipronil is another common ingredient to look out for. It’s an insecticide that kills adult fleas and larvae, chewing lice and ticks. But it can also cause hormonal disruption, heart arrhythmia, dermatitis, and is considered to be a possible human carcinogen (a substance capable of causing cancer in living tissue). Frontline is the most widely used pet product that contains this undesirable ingredient.


Just this month, the FDA issued a warning for pet owners and veterinarians regarding isoxazoline. This drug is found in Bravecto, Nexgard or Simparica. Recent data indicates that pets using these products have experienced neurologic adverse effects like muscle tremors, ataxia, and seizures.

Other dangerous but common insecticides in flea and tick preventatives include permethrin, pyriproxyfen, methoprene and other aryl heterocycles. They all carry risk factors for both pets and humans, including risk of cancer.

There ARE safe alternatives!

The lesson to take home here, is not to be afraid, but to be informed. Read the labels on any and all products you bring into your home, especially those you’re giving your pet. Some pets are more sensitive than others to certain ingredients, so a natural or holistic veterinarian may be able to offer you the best advice and give you safe suggestions for pet pest control.

There are plenty of ways to keep your pet free of fleas and ticks, and also keep the little creepy crawlies out of your yard and home. Check them out in my blog post 6 Safe Flea Treatment Options for Your Pet and Home.

If you’d like a customized plan for keeping your pet flea-free and healthy, or healing any damage done by chemical exposure, you can reach out to me by scheduling a consult or emailing us at drruthroberts@drruthroberts.com. I’m your pet’s ally, and always here to help!

Dr. Ruth Roberts DVM, CVA

Dr. Ruth Roberts Holistiv Vet

Dr. Ruth Roberts is The Original Pet Health Coach, and has supported thousands of dogs and cats to overcome health hurdles like kidney disease, GI Illness, allergies and cancer. Her natural approach to healing creates a gentle yet effective path for your pet to take on their journey to wellbeing. Dr. Ruth created The Original CrockPet Diet, a balanced home cooked diet for pets, as the foundation of health. Dr. Ruth is now training passionate pet parents, and pet professionals to be Certified Holistic Pet Health Coaches so that more pets can be helped holistically.