Options for Flea and Tick Treatments

Options for Flea and Tick Treatments

2021 Jun 15th

It’s that time of year again! The sun is shining, the birds are singing, and the fleas and ticks are on the prowl! Time for a flea and tick product for our pets. However, you should be aware of some of the risks associated with common treatments. There are six different kinds of flea and tick treatments and preventions that we will discuss in this post. They are Chemical Oral Pesticides, Chemical Topical Pesticides, Chemical Flea Collars, Natural Scent-Based Flea Prevention, Natural Pesticides, and Diatomaceous Earth. We will go over the pros and cons of each so you can make your own decision as a well-informed pet-parent.

Chemical Oral Pesticides


  • Easy to give
  • Effective for three months
  • Kills biting insects quickly
  • Goes through bloodstream and is throughout their entire body


  • Many serious side effects, including seizures and death
  • Pest must bite the animal
  • Made with toxic chemicals
  • Cannot be given to young animals due to risk of toxicity
  • If they get a side effect, cannot remove the cause

These oral pesticide-based flea and tick treatments are becoming more and more popular. They come in treat form and are typically given once every three months to adult pets ONLY. I have seen instances of these treatments being recommended to puppies, but DO NOT do this, it is not recommended by us OR the companies that make them! The chemicals are absorbed into the blood and spread throughout the body. When an insect bites the animal, they become poisoned. However, these oral treatments have many serious side effects, including ataxia (loss of control of bodily movements), tremors, seizures, vomiting, the list goes on (1). All four that are on the market contain chemicals known as isoxazolines. These compounds block nerve signals, causing insects affected to become paralyzed and die. Unfortunately isoxazolines do not just affect insects, they also affect the nervous systems of the pets that take them.

For example, Bravecto is a common oral pesticide flea and tick treatment many pet owners are giving their pets now. However, the active compound in Bravecto, Fluralaner, since 2013 when it was introduced into the market as a pesticide, has caused at least 783 animal deaths as informed by the FDA, and these are just those that have been reported.

A study was done on its safety with 294 dogs given Bravecto (2). The study reported “only” 7.1% of them had side effects, including lethargy, vomiting, diarrhea, and decreased appetite. This may not sound like a lot, but consider a sample of 10,000 pets, the approximate number of pets in a town with a population of 30,000 people, given these chemicals. Based on this study and the reports from the FDA, that would mean 490 of them would have minor reactions, an additional 196 of them would have major side effects, and another 14 would die in an 18 month period. A minor side effect includes something like vomiting and diarrhea with no blood, dilated pupils, irritability, etc. A major side effect would include lethargy, bloody stool, nervous system and cardiac malfunctions, among others. On top of these reports, there were over 7000 reports of the drugs not working as intended (not killing fleas and ticks within the dosage period).

If you give your pet this treatment and they do develop side effects, you cannot remove the chemical from their body. However, there are some things you can do to try and help them eliminate the cause. Giving your pet food grade diatomaceous earth can bind chemicals and help it pass through the digestive tract without being further absorbed. Pair this with a kidney and liver flush to help them excrete the harmful compounds more quickly.

Chemical Topical Pesticides


  • Low toxicity to mammals topically
  • Kills insects on contact
  • Easy to apply
  • Can be washed off if side effects occur


  • Must reapply every month
  • Moderately toxic in ingested and highly toxic if inhaled
  • Some are deadly to cats

Topical pesticides are the most common form of flea and tick control and require putting a tube of liquid pesticide on the back of an animal’s neck. Many companies state that the natural oils and movements of the pets cause the chemicals to spread throughout the pet’s coat. These treatments kill pests on contact, which means that the insects do not need to bite the pet to be poisoned. When administered dermally like this, they have low toxicity to the host and can exhibit minor side effects such as irritated, itchy skin and redness.

However, when the pesticide spreads to the entire surface of the animal, this gives them access to licking it off themselves. Also, other pets in the household and people petting them are at risk of being directly exposed. This can be a problem since when ingested these pesticides are classified as Moderately Toxic and can cause side effects such as vomiting, nausea, diarrhea, and lethargy (3). Also, when inhaled it is classified as Highly Toxic and can cause ataxia, tremors, liver damage and possibly death.

An example of a topical treatment is Advantage and its dog-only counterpart Advantix. Imidacloprid is an active ingredient in both formulations and binds nicotinic receptors to cause paralysis in insects, and even mammals. These receptors are only located in the central nervous system in insects but are also located on muscles in mammals. The receptors in mammals are less sensitive than those in insects. The goal is to give the animal a dose that will be effective against insects but not our pets. Therefore, it is important to use a dosage appropriate for your size of dog or cat if using these. I have heard many people talk about buying the big dog version and splitting it up among their smaller pets. Do not do this as this can be very dangerous since you will not be giving an exact dose and put them at risk of overdosing. If they do develop a side effect, quickly wash it off with dish soap or human shampoo since dog shampoos tend to be too gentle. If imidacloprid does get ingested, it is advised to give them a liver and kidney cleanse to aid the body in eliminating the chemical; on the plus side 96% of imidacloprid is excreted within 48 hours if ingested.

The other version, Advantix, should never be given to cats. The chemical permethrin that they add to this formula cannot be metabolized by cats and will therefore stay in their system and is highly toxic to them. Permethrins are neurotoxins that paralyzes insects but can also destroy mammalian liver cells. The Environmental Protection Agency classifies permethrins as possible carcinogens as well (4).

Flea Collars


  • Very easy to use
  • Low toxicity if kept external
  • Kills insects on contact
  • Can be removed if side effects occur


  • Moderately toxic if ingested and highly toxic if inhaled
  • Very accessible to their mouth and others in the household

Many flea collars use the same or similar compounds as the topical treatments and are accompanied by the same risks and benefits. Because there is no application or feeding, you simply put the collar on, they are very easy to use. However, this makes them very easy to access, which is especially dangerous for other household pets and children that may touch the collar and then their mouth, or lick/bite it.

Natural Scent-Based Flea Prevention


  • Typically safe
  • Deters bites from insectsRelatively easy to use


  • Do not kill insects
  • Does not stop bugs from biting, simply deters them
  • Must be reapplied often, usually every day

These types of flea and tick prevention generally come in two forms, a spray or a chewable pill. Both typically are comprised of herbs and essential oils that fleas and ticks are not fans of, such as lemongrass and rosemary. They do not kill fleas but create an aroma about the pet that insects do not like. This deters the bugs from crawling on pets but is not perfect. If insects are desperate, they will tough it out and bite anyways. They usually wear off relatively quickly and need to be reapplied often in order to stay effective.

These products are generally regarded as safe since they are plant-based and natural. However, not every natural product is completely safe! Many essential oils are made using harmful solvents such as propylene glycol. It is advised to make sure the essential oils in products are not made with these chemicals. Steam distillation is the best process for making a pure, high quality essential oil; check to see if the manufacturer knows what process is used in their essential oils.

There are also many essential oils that are harmful to pets, cats being especially sensitive. For example, tea tree oil is very popular, but is toxic to a cat’s liver since they cannot metabolize it. Another example is cedar wood oil. If you see cedar wood oil in a product, such as the Virginia Cedar Oil in LifeForce spray, make sure that it is not Western Red Cedar oil since this oil can be toxic due to the high level of phenols in it. Other cedar oil is most likely safe, but just make sure you read and research before you buy something, whether it is natural or not.

Natural Pesticides


  • Longer lasting than scent-based
  • Kills fleas and ticks
  • Deters insects from walking on pets and biting
  • Safe for mammals with no side effects
  • Effects entire body of animal
  • If given too much acts as a digestive supplement


  • Can taste bad
  • Trickier to give to pets
  • Bug must bite to die

Natural pesticides are hard to come by. Some come in spray form, such as cedar wood oil. These have been shown to kill fleas, but like I mentioned above be careful as to which cedar tree they are using to extract the oil from, as well as the process they are using.

The other form that exists is natural pesticides that you feed to your pet. Searching online, our Earth MD Flea and Tick Prevention is the only one we could find that works this way. The main ingredients, quassia bark and neem leaf, contain compounds (quassin and azadirachtin, respectively) that are toxic to insects, but not mammals. When the pet consumes it, these compounds go into their bloodstream and spread throughout their body. When a bug bites them, these compounds make it so the insects cannot eat or reproduce, and then they die. This formula also contains garlic which makes the pets deterrent to insects, so the bugs do not want to walk on them in the first place for added protection. These compounds stay in the blood for a couple of months once saturated, so treatment only needs to be done for a week every other month. The downside is it does not taste very good (another name for quassia bark is bitterwood), but there is no worry about side effects, so just mix it with something tasty and you are good to go!

Diatomaceous Earth


  • Kills insects mechanically from contact
  • Easy to apply
  • Can be applied to furniture and floors for infestations


  • Messy
  • Must keep reapplying it
  • Difficult to use on long-haired breeds

Diatomaceous earth gets its own category because it works in a very unique way. Unlike all of the other products that kill insects, it does not kill them by poisoning them. Instead, it is abrasive to the insects and as they walk on the diatomaceous earth, it rubs off the waxy coating of their exoskeleton and draws out moisture. This process essentially dehydrates the bugs until they die. This is effective against all insects, even ants and small roaches! Diatomaceous earth is a great product to have handy around the house.

To use it on your pet, simply sprinkle it on them and rub into their fur until it gets to their skin. This can be quite messy since it is the consistency of flour, so make sure you do this outside. It can be difficult to get under the fur of long-haired breeds, but it works great on pet beds and furniture. You can sprinkle some along baseboards and doorways to keep insects out as well. Because it is a powder, it does need to be reapplied as it falls off or if the pet gets wet.

Diatomaceous earth is safe externally, as well as internally (they can eat it), as long as it is the FOOD GRADE version! The diatomaceous earth sold at Canadian Tire and the like that are meant for gardens and pools are NOT food grade! Do not feed these to your pets, it is too abrasive and cut with toxic ingredients. Food grade diatomaceous earth is finely ground and over 90% pure, so make sure you read the label before you buy it. Most pet foods stores will have a food grade diatomaceous earth, such as our Earth MD brand.

(1) https://www.fda.gov/downloads/AboutFDA/CentersOffices/OfficeofFoods/CVM/CVMFOIAElectronicReadingRoom/UCM622678.pdf

(2) http://yourpetsneedthis.com/latest-greatest-flea-control-dogs/

(3) http://npic.orst.edu/factsheets/archive/imidacloprid.html

(4) https://www.dogsnaturallymagazine.com/the-dangers-of-permethrin-for-dogs-is-your-flea-bandana-safe/