I have written several times in the past about my feelings on flea and tick control products, so it is about time that I write in more detail about what I have discovered while doing research on the subject. For full transparency, my first dog may have been killed by a spot-on flea treatment. This is what I wrote following his death in 2010 on this blog:

**Question drugs.** Knowing what I do now about the horrible toxins we subject our animals to, I will never apply another dose of flea medication even if it is recommended. I gave a few doses to Mikey at the advice of a vet after he suddenly began scratching incessantly and the “most likely culprit” was flea dermatitis (even though he had no evidence of fleas). I don’t know if the Frontline killed him, but knowing how many dogs it does kill, and that it probably causes AIHA in some, my dogs will never get another dose of those horrible toxins again. It doesn’t make sense to apply medications that I am not supposed to get onto my skin – that is simply way too frightening, given there are so many safer alternatives.

The same will go for other overly prescribed medications (steroids, worming medications, and so on) and vaccinations, and we are now going with holistic vets, titers, and home-cooked meals for our animals. The thing that angers me the most is I *knew* this long ago with my cat, and somehow lost my way. Mikey helped us get back on track – we are (again) considering everything that goes on or into our companions.

But most of all, Mikey’s passing taught us to take the difficulties of our lives and instead of letting it get us down, to let it propel us to something positive. I am taking what he gave me, and putting it to good use: improving the way I care for myself and for my companion animals.

We do not know if he was killed by a flea control product, or a vaccination, or both; however, I do have suspicions that the pesticides may have built up in his system, or interacted with a vaccine or something else he ate. And while we do not know for sure, other dogs have strong evidence to suggest that they have. As a result, I have done a lot of research and investigation to figure out if it was a possible cause (it is), and also what are safe and effective alternatives for flea and tick control. I will share some of this research here.

Important note: I am not a veterinarian or health professional. The following information is based on research online and discussion with my own veterinarians, and is my personal opinion about these products based on the information and evidence I have found. I encourage all readers to conduct their own research into these products, that hopefully considers the following information, and draw your own conclusions about the direction to take with your canine companion’s care.

What flea and tick control products contain pesticides

Spot on flea medication by cyborgsuzy

“Spot on” flea and tick products, flea collars, and other medicines such as oral medications contain ingredients that could be hazardous to your pet’s health. Many of these active ingredients attack the nervous system or otherwise incapacitate the pests that are targeted, such as fleas, ticks, or heartworms. The flea and tick control products often include pesticides and other chemicals that can also trigger reactions in your dog (side effects), and this can also include triggering illness and disease. Sometimes these diseases are underlying conditions you were previously aware of, and other times the condition is a mystery. It’s also likely that we don’t know a lot of what these products could cause as well, as the flea and tick control products have been suspected as a trigger for certain illnesses but the evidence is still anecdotal.

Products that contain pesticides include Frontline, K9 Advantix, Sentinel, Comfortis, Advantage, Program, and Revolution (and many other brands).

Why are they dangerous for my dog or cat?

Spot on, or topical, treatments contain pesticides that enter your pet’s bloodstream like pill or medicine treatments do. Lets look at Selamectin, the active ingredient in Revolution. This pesticide is applied on your dog’s skin, and is then absorbed into his body through the skin and hair follicles. The pesticide then travels through the bloodstream, intestines, and sebaceous glands of your dog, and parasites then ingest the drug when they feed on your dog’s blood.

These products vary in how hazardous they are to your pet’s health, given dosage levels and the type of pesticide that is utilized in their formulas. Some ingredients are safer than others, but will still carry risk even to a healthy animal. If you choose to use these products, it is very important to read the labels, and learn about what you are putting into your companion’s system. Research each ingredient closely, and see what other pet guardians have to say about their dogs reaction to the ingredient. As far as I can tell, there are a lot of unknowns about these insecticides and how they really affect dogs of varying sizes, breeds, and genetic lineage (not to mention conditions, such as epilepsy), so it is important to also consider what other pet guardians have to say about what happened after giving their dog these drugs.

First, a look at Frontline. Frontline uses Fipronil for pest control. It is a toxin that is described as “a slow acting poison” and even carcasses of the pests killed are toxic if consumed. Another concerning aspect of this toxin is that “fipronil has been classified by the EPA as a Group C (possible human) carcinogen based on an increase in thyroid follicular cell tumors in both sexes of the rat.” So while deemed safe for use by the FDA, it is worthwhile to take the entire picture into consideration before having this toxin enter your dog’s bloodstream for pest control. It should also be noted that “flea populations appear to be developing a genetic resistance to its effects” (in regards to Frontline/Fipronil, and I have heard this about competing products as well).

Lets look at what is considered one of the “safer” products on the market, Comfortis (spinosad) and Trifexis (spinosad and milbemycin). These ingredients are marketed as safer than competitors and sometimes “completely safe” – at least, this is how it was marketed to me by more than one vet – yet there is still a lot of anecdotal evidence that suggests dogs become ill and sometimes die not long after they are given this insecticide. As far as I can personally tell, due somewhat to how new this product is, there is uncertainty about whether this product is indeed safer than alternatives. There is also a scientific study to be aware of that suggests Spinosad and Malathion induce “markers for long term mutagenic effects in mammals” although other studies did not show tumor growth when given to rats for two years. At any rate, it’s possible that more study may be required to determine safety of longterm usage.

Evidence of harm to dogs and cats
So while we may not have a definitive answer on the cause of these illnesses, there is a vast amount of anecdotal evidence that points at a correlation between giving these products to your pet and a risk of mild to severe side effects. And, I feel that it’s important not to ignore such evidence.

To find such anecdotal evidence, do a search for the flea and tick control treatment you are considering and combine it with words such as “side effects”, “sickness”, “AIHA”, “IMHA”, “hazardous” and so on. If your dog has an underlying condition that you are unaware of, adding a pesticide to the system can cause a dangerous reaction. Of course, you’re searching for the negative and are more likely to find scary stories instead of success cases, but you’ll find real-life stories of people who have been affected by these products. And this is important information to consider. There are many dogs who are fine, of course. But many others who are not, and these stories also do not account for any mysterious illnesses that may or may not have been caused by these products – whose illnesses may have been triggered after subsequent exposures or unknown interactions. My dog is one of these statistics.

So do your homework, and question everything that you put on or in your pet. Remember that what goes on your pet also often ends up in your pet – just like external creams and ointments can affect our own health by absorbing into our system on a regular basis. The point of this article is that there are safe alternatives to pesticides, so taking a gamble on safety by adding chemicals to your dog’s bloodstream is not necessary. There are alternatives available that can also work for pest control.

What I use for flea and tick control


Dogs wearing a ShooTag. Do note I now sew little “pockets” that hide it between their collar and neck, which is a better way for them to wear the tags.

I was introduced to Shoo Tags by a local pet enthusiast, who told me that many people in the area swore by the product as a flea and tick repellent. I was in the shop looking for a new natural essential-oil spray for my dogs, as it was tick season and I was concerned about our upcoming hikes. We had used some natural oil sprays, and were still dealing with ticks after our hikes every single time.

So I decided to try the Shoo Tags, and lo-and-behold, no more ticks on subsequent walks or hikes even when long grass was involved. Also, no more fleas milling about the dogs a few days after hanging the tags from their collars – we were always combing at least a few out of their fur, and the fleas and scratching disappeared. These tags use a frequency built into a magnetic strip (like those on credit cards) to repel pests and it seems to be effective.

What really convinced me was when we put a tag on our cat. Flea season started, and she was the only pet in our house without the tags on her collar. We were waiting to see if fleas would be problem, given our dogs had the tags on and she is an indoor cat. Sure enough, she got fleas – and was the only pet in our house to get them. I purchased tags for her, and added them to her collar. Within a couple days, the fleas were gone with no other involvement from us (I was testing to see if the tags were effective). She doesn’t get garlic, so that wouldn’t be a cause of the fix. So it could be coincidence, but three pets in and before: fleas and ticks, and after the tags: no more pests.

The advantage of using the tag over other solutions is I don’t need to remember to use the essential oil spray regularly, I don’t need to remember to feed a supplement (such as garlic or dichotomous earth, although I do include garlic in their diet), I just mark the calendar and replace a tag on their collars. Biggest advantage? I’m not putting a pesticide into the blood stream of my beloved companion.

Note: I have in no way been compensated for this article (product or money). I am simply a happy (and relieved) customer that no longer has a flea and tick problem – whether it’s this product or by coincidence, I’m happy.

Other alternatives for flea and tick control

Yes, there are several different alternatives – too many to describe in this short article!

I have used dichotomous earth with some success, although even with the food-grade (safe) varieties you have to be careful that you and your pets do not inhale the dust. This combined with regular bathing and combing can alone keep a minor to moderate flea infestation at bay. I still have a small amount of garlic in my dog’s diet, and I strongly recommend feeding a high-quality diet which both keeps your animals healthy and also aids in deterring pests. Speak with a holistic veterinarian for a recipe that includes supplements like garlic and other organic herbs to help with pest control. There are other supplements, such as brewers yeast, that can be added to the diet or given in treat form.

Prior to using Shoo Tags, I used essential oil sprays from my holistic veterinarian with some success – perhaps more success with better and more regular application.

There are also home-grown solutions. I heard of people with huge tick infestations spraying Listerine around their yard, and completely solving their problem. Ticks apparently hate Listerine. I have read of many interesting alternatives used by people to solve these problems that do not involve toxins and poisons.

And if you do end up resorting to a pesticide, do take the frequency of application with a grain of salt – often you do not need to apply them every month, and a less frequent schedule is more than enough to control the pests.

UPDATE November 2016: This is our current protocol for fleas this year, and we had success during a particularly bad year for fleas. Currently I’m feeding a raw diet that includes a variety of herbal additions (added into the grind by our raw supplier). In addition to that I add Springtime Bug Off Garlic for Dogs (and a few other things – kelp for teeth, an oil blend for skin/coat, whole-food chlorella, and calcium – required since their grind does not have enough). In particularly intensive times of year I add brewers yeast as well as an essential oil spray (from my holistic vet) just for some extra peace of mind. We use FleaBusters powder on the carpet.

If you are considering a home cooked diet from a recipe, I encourage you to find a trusted holistic vet that is well researched on the topic (nutrition) and home cooked diets and consult with them for an appropriate recipe for your dog. This will vary depending on their individual needs. Also, read as much as you can on the topic from trusted and unbiased sources. Make sure any studies you read are independent and peer-reviewed, and not funded by vested interests (dog food companies, supplement companies and so on). Good luck!

About Author

Jen deHaan is graphic designer, small business owner, and dog person living in Bay Area, California. Jen enjoys learning about dog training and behavior, and has taken several courses and seminars since 2010. She also contributes articles to leading websites, such as Victoria Stilwell's Positively . It all started with a great dog called Mikey (aka "dude"), loved and lost but remembered forever. Jen also runs a freelance business focusing on graphic, web, and UI design at FoundPixel, and a small business creating hand crafted dog products at Stylish Canine.