Dangers of Spot On Tick Chemicals


NRDC Issue Paper April 2009 Poison on Pets


NRDC Issue Paper April 2009 Poison on Pets II

Dangers of Insecticides

Using bio-spot insecticides on dogs to repel ticks are the most popular method of tick control. These chemicsls are applied topically between the pet's shoulder blades. It collects in oils from skin and hair follicles and migrates across the pet's body. These liquid spot chemicals are easy to apply and are highly effective, however, they are highly toxic chemicals and pose a very real hazard to your dog. These dangers include a possible severe alergic reaction to seizures and cancer. We do not recommend using these products.

Bio Spot Victims - www.biospotvictims.org


This pestiside is classifed by the U.S. FDA as "likely to be carcinogenic to humans". The following products use this chemical as their active ingredient.

When a tick bites a dog that has this chemical applied, it will die within 12 hours preventing the passage of the B. burgdorferi. (Permethrins should NOT be used on cats.)

National Pesticide Information Center Fact Sheet for Permethrin


Deltamethrin is an insecticide belonging to the pyrethroid family. 


Is classified as a Group C (possible human) carcinogen based on an increase in thyroid follicular cell tumors in both sexes of the rat.

Warnings about Fipnoril

FrontLine (by Merial, a joint venture between Merck and Aventis) is a popular flea and tick treatment for pets. It contains 9.8% fipronil by weight.

FrontLine is applied topically between the pet's shoulder blades. Fipronil collects in oils from skin and hair follicles and migrates across the pet's body. Typically 98-100% of any fleas or ticks die within 24-48 hours. This toxic action lasts for approximately 30 days.

study found that, one day after applying FrontLine to an adult dog, petting it for just 5 minutes while wearing gloves resulted in exposure of 600 ppm. There are indications of carcinogenic action in rats at 300 ppm, The EPA RfD for fipronil is 0.0002 mg/kg/day. This is a concentration of 0.2 ppb.

Typical owners handle their pets more than 5 minutes per day. Also, any surface the pet contacts will become contaminated, thereby increasing exposure. Children and anyone suffering an excitoxin-related illness are at higher risk. Veterinarians and other pet care providers also have increased risk.


Very few tick collars are effective with the exception of a collar that contains amitraz. Amitrazis an organophosphate that is very effective at repelling and killing ticks, but has little effect on fleas. Often using a once-a-month topical product along with a Preventic® Collar provides the best protection.

Additional References

SimpleSteps.org - Site has nearly all collars and details of the harmful chemicals.

List of all Products with Ingredient Warnings