Your Pets

Is Your Flea & Tick Medicine Doing More Harm Than Good?


If you are a pet owner or someone who works with pets, you know how important it is to keep our furry friends free of fleas and ticks. However, you may not know that many products commonly used to treat fleas and ticks, including spot-on treatments, collars, sprays, and foggers, contain chemical pesticides that can easily spread around your home and make it into our waterways. These photos were taken from a study where researchers used a fluorescent dye in a spot treatment to show how it can spread.

Because of this, the safest option for our homes and waterways is using oral flea and tick medications as well as non-chemical methods for keeping fleas and ticks off our pets.

The California Department of Pesticide Regulation (DPR) has reviewed the use of fipronil (a common ingredient in pet/carpet sprays and on-pet topical treatments) and found a potential human health risk to adults and children in households where sprays and topicals are used.

In addition, flea treatment products have been found in wastewater, sometimes at concentrations that are toxic to sensitive aquatic species.


To avoid exposing pets, their owners, and Bay Area waterways to toxic pesticides from harmful chemicals, pet owners and professionals are encouraged to use oral medications instead of topical treatments.

Not only do oral medications reduce exposure to toxic chemicals, they also may be more effective than topical spot treatments. According to scientific studies, oral flea and tick medications appear to be a safer and more effective alternative to topical treatments and collars. This is possibly because they are easier to use as directed. 

Furthermore, spot-on topical treatments only reach about 5% of the fleas in your home. It is estimated that adult fleas account for only 5% of the total flea population. The remaining 95% of a flea’s life-span is spent as eggs, larvae, or pupae which they lay around the home. 

Understanding the flea cycle is key to solving flea infestations. Less than 5% live on your pet; the rest are in different stages of the life cycle spread throughout your home.


How To Avoid Flea & Tick Pesticide Pollution


For pet owners, the following is a list of recommendations to keep toxic pesticides out of your home and our bay. 

For veterinarians and other animal-care professionals, we encourage you to share these recommendations with your clients for the benefit of your, their, and our water’s health.


1. Speak to your vet about oral medications to protect pets against fleas, ticks, and other parasites.

    • Work with your veterinarian to select appropriate oral medications to protect your pets.
    • If additional topical flea control is needed, consider using flea shampoos or dips that contain pyrethrins. Pyrethrins are much less toxic than other flea shampoo chemicals.


2. Avoid products that contain toxic chemicals.

    • Avoid using external or topical flea / tick treatments such as collars and spot products in order to avoid exposing your pets and family to toxic chemicals. 
    • Avoid house sprays, foggers, and house “bombs”. These items have limited effectiveness and produce a lingering residue. 
    • Avoid treatments containing chemicals that are highly toxic and harmful to the environment, including fipronil, indoxacarb, imidacloprid, bifenthrin, deltamethrin, and permethrin.


3. Clean your home regularly and thoroughly to prevent flea problems before they start.

    • Vacuum carpets, floors, furniture, and inside cracks. Reduce clutter around your home to improve the effectiveness of vacuuming and dusting. If you are able, consider replacing carpets with hardwood floors.
    • Wash pet bedding and other fabrics that pets touch regularly, including human bedding.
    • Use flea combs. Dip the comb frequently into soapy water in order to capture and drown fleas.
    • Use flea traps to help determine the size and location of the infestation. You can make your own flea trap by putting soapy water in a shallow baking tray and leaving it in a room overnight with a small lamp aimed at it. The results will be visible in the morning.


4. Avoid ticks attaching to you or your dog:

    • If possible, keep your dog’s coat short. 
    • Try to keep out of the brush. Walk in the center of trails and use shorter leashes when walking in the woods or grassy areas to keep your dog from wandering too far off-trail.
    • Thoroughly inspect your pet after walks before ticks have time to attach. Pay particular attention to the nose, mouth, eyes, ears (inside too), around tails and under the collar. Inspect yourself and your gear as well. 
    • Seek to create a tick-free zone in your yard by controlling bushes or tall grass. To restrict tick movement, consider providing a 3-foot barrier-gap (e.g., wood chips or gravel) between lawns and wooded areas. Keep play and deck equipment away from yard edges. Keep outside areas neat to discourage rodents or other wildlife.


5. If a tick has bitten your dog

    • Remove it as soon as possible and watch your dog for tick-borne illness. Symptoms of these illnesses include lethargy, lameness, loss of appetite, and vomiting (for additional insight on symptoms and treatment, see the AKC Canine Health Foundation).
    • The duration of tick attachment required for disease transmission varies. Diseases can also be transmitted when dogs ingest either living or dead ticks. 
    • Consider keeping the tick: You may want to provide the tick to your veterinarian so it can be tested for diseases. Consider submitting the tick to your public health department/vector control or to, an organization providing testing of ticks nationally.


6. Dispose of unused pet medication safely

    • Never flush old, unused pet medication! Instead, use the Earth911 Search Engine to find a safe disposal location near you.


Speak to your vet for more information on how to handle a flea infestation.


For Veterinarians 

For more resources (including references to scientific studies), visit here.  


*The photos above are part of a study where researchers incorporated a fluorescent dye into the spot treatment to photograph the spread. Photographs are reprinted from Bigelow Dyk, M., et al. (2012). Fate and distribution of fipronil on companion animals and in their indoor residences following spot-on flea treatments, Journal of Environmental Science and Health, Part B: Pesticides, Food Contaminants, and Agricultural Wastes, 47(10): 913-924. Reprinted by permission Taylor & Francis LLC.