Skip to main content

Verified by Psychology Today

Are We Offering Our Dogs Treats—or Toxics?

New studies illuminate hidden chemical dangers to dogs.

Key points

  • Dog owners need to be alert to hidden hazards facing pets.
  • Pet toys and foods can expose dogs to endocrine-disrupting chemicals.
  • Recent studies of dogs’ exposure to toxics have been done via fur analysis.
  • Dogs that live in human homes have dramatically higher PFAS levels than livestock.
Norman Scott, used with permission
Source: Norman Scott, used with permission

Since COVID, my home has resembled a clearinghouse. A steady stream of trucks arrives to deliver household goods, clothes, groceries, and—most importantly according to our dog, Bernie—pet food and treats.

My husband recently opened one of these packages and smiled as he withdrew a soft, stuffed plush toy from its recesses. It was a gift for Bernie. A raccoon, to be exact. Mr. Raccoon had been ordered in honor of the live ones who parade across our overgrown property and trees, taunting and infuriating our canine ward.

Bernie received his gift with interest and curiosity. After a few enthusiastic rounds of toss-and-chase-the-airborne-creature, Bernie scampered off, tail streaming like a flag, with Mr. Raccoon secure in his jaws. He settled in a far corner of the den and set about mouthing and tasting the newcomer from every angle.

By dinnertime, the dog had an odd, glassy-eyed look.

It didn’t appear he was choking, but he seemed a bit swollen. I placed a gentle hand on Bernie’s flank and discovered a disturbingly fast and jerky vibration, as if a small motor was grinding beneath his fur, trying to shift gears. Yikes!

My first thought was: Why do health crises always arise after the veterinarian’s office is closed? My second thought was: What have you done, Mr. Raccoon?

I hunted down the suspect and found him intact: no torn fabric, all stuffing present and accounted for. Still, the polyester faux fur was slimy, soggy, and matted. Fortunately, Bernie’s distress passed, but to be safe, Mr. Raccoon was banished.

The Risks of Toxic Exposure to Dogs

Days later, a package arrived that confirmed our caution. In their new book, The Forever Dog: Surprising New Science to Help Your Canine Companion Live Younger, Healthier, and Longer, authors Rodney Habib and Dr. Karen Shaw Becker lay out the stark scope and depth of hidden hazards that dogs face when sharing our human lifestyle.

The possibility of hidden toxics didn’t completely surprise me, since they played a role in my own health crisis years earlier. As a result, I had switched to “cleaner” foods and thought carefully about lifestyle choices. For example, a reverse osmosis water filtering system installed in the kitchen now removes contaminants from our drinking water. And of course, this purer water fills Bernie’s water bowl too.

But what had I overlooked?

I was already suspicious of plastic and rubbery toys because of the possibility of phthalates, common substances used to make plastics flexible. These substances are known to disrupt normal endocrine functioning and are toxic to reproductive cells. Higher urine concentrations of phthalates, and particularly the phthalate known as DEHP (di-2-ethylhexylphthalate), are correlated with higher death rates in people 55-64 years old, according to a new study in Environmental Pollution.

I asked Dr. Becker, one of The Forever Dog’s authors, about the potential risks of a dog mouthing and carrying around a plush toy made from synthetic materials, and the practice of stuffing rubbery toys with food and giving them to dogs as a chew treat or distraction.

With respect to pet toys, she replied, “Most are imported. They aren’t required to go through any testing for safety or contaminants and most don’t have ingredient labels, so in short: Buyer beware.”

Assessing Hazards

Dr. Becker and others are paying close attention to how modern lifestyle hazards trickle down to pet dogs. Researchers are analyzing dog hair for toxics, a lab technique formerly reserved for studying human exposure.

  • A recent study in Science of the Total Environment analyzed the fur of indoor dogs living in Poland using liquid chromatography-tandem mass spectrometry. All dogs had detectable levels of parabens, which are commonly used as preservatives in processed foods (including dog food), lotions and cosmetics, and pharmaceuticals. High levels of parabens are linked to breast cancer in women.

    The study’s younger dogs and male dogs had higher levels of parabens in their fur. The authors speculate that “frequent use of cosmetics containing parabens by the pet owner or frequent house cleaning, may be relevant for pet animal exposure to parabens.” Also, higher concentrations of methylparaben were detected in male dogs and could be linked to its role as a pheromone scent that plays a role in dog mating.

  • Fur analysis of 30 dogs in an October 2021 study in Environmental Pollution found industrial chemicals called perfluoroalkyl substances (PFASs) in all dogs tested, and at a significantly higher rate than that found in farm livestock. PFASs are used for food packaging and other purposes and are linked to harmful health effects such as kidney and testicular cancer.

    This high level, say the authors, “is probably connected with the fact that dogs live in the immediate vicinity of humans, spend much of their lives indoors, and are exposed to higher concentration[s] of PFASs in toys, food, bedrolls, and things used by humans.”

A 2020 study found that half of babies’ plastic toys tested contained substances with significant estrogenic activity—in other words, cause hormonal disruption—so it’s not much of a reach to assume pet dogs face similar hazards.

What Can Owners Do to Keep Pets Safe?

How can responsible pet guardians truly know how much toxic exposure is winding up in their beloved companion from plastic pet toys? Or from routine household choices—such as fabric softeners, fragrances, personal grooming products, and weed killer, and even the synthetic grass or rubberized flooring found in dog kennels, dog daycare, and dog sport or training facilities.

“The consequences of exposure to potentially harmful environmental substances depends on body burden, frequency of exposure and genetics (the body’s ability to metabolize or clear environmental toxics) and route of exposure,” explained Dr. Becker. “Unlike human family members, pets don’t shower regularly and are naked, which means pets may have more exposure, not to mention they groom themselves with their mouths.”

After immersing myself in this information, I now question letting my dog “kiss” a friendly visitor, when their face is covered in makeup and sunscreen likely full of parabens and phthalates. And what about the unseen residue Bernie picks up from lawns or sidewalks doused in toxics? How will the cumulative effect of toxic exposure affect his health and behavior?

“I think it’s safe to say our pets have ongoing exposure to higher than previously thought levels of endocrine-disrupting chemicals,” said Dr. Becker. “The extent to which these chemicals affect physical and mental wellbeing has yet to be explored, but knowing endocrine imbalances can and do affect mentation [mental activity] and behavior, we’re all anxiously awaiting further research to confirm our suspicions!”

Safer Lifestyle Choices

I was serving Bernie meals purchased at the vet’s office, assuming they were premium quality. But The Forever Dog points out that canned foods and shelf-stable items like kibble are treated with additives and high heat, leaving them chock full of cancer-implicated toxics. Even cans alleged to be “BPA-free” may contain equally toxic replacements. The typical American pet meal is a veritable alphabet soup of unwelcome substances.

How can a caring pet parent minimize toxics?

  • Give fresh foods, such as carrot slices or kale stalks, for chew treats and meal toppers.
  • Phase-out canned foods and especially kibble, which is full of acrylamides according to a new Japanese study. Explore minimally processed foods—such as refrigerated, frozen, or freeze-dried options—that are marked as containing full nutrition. For those willing to prepare fresh dog food in your own kitchen, kudos—but be very cautious to include the correct mix of vitamins and minerals, or you can inadvertently cause serious health problems.
  • Choose “greener” household cleaning products and toss common fragrance products, including “room fresheners.
  • Be cautious about letting dogs gnaw and suck on plastic and synthetic chew toys. Avoid plastic food bowls, and do not be lulled into a false sense of confidence by the label “BPA free.”
  • Frequently vacuum and wash areas in the home that gather dust, which traps toxics, especially if you live near highways, areas treated with weed killer, or industrial facilities.
  • On walks, steer clear of lawns, gardens, and walkways that have been sprayed with pesticides and weed killers. If you must walk in these areas, consider washing the dog’s paws afterward. The Forever Dog contains a recipe for such a wash.
  • Choose dog bedding made of natural, untreated fibers. Skip (or safely cover) furniture fabrics that are chemically treated for stain resistance or with fire retardants.

Boost Immunity

Fortunately, we can support dogs’ natural resistance to toxics in two easy ways. One, by giving regular, plentiful exercise to optimize the natural immunity system. Dogs kept crated or physically confined for long periods are at heightened health risk due to inactivity.

Second, we can employ time-restricted feeding, in which food and treats are given only during limited, set hours each day. This allows dogs’ organs and systems important downtime to efficiently gather and discard biological trash.

For Bernie’s sake, I plan to scrutinize labels on toys, chews, and food. My next DIY project will be crafting a toss toy from old cotton T-shirts or jeans that have been washed in unscented detergent without fabric softeners. (Undoubtedly, the resulting toy will not resemble Mr. Raccoon, but hopefully, Bernie is forgiving.)

I will think more about what the dog’s feet, mouth, and nose contact regularly. With more informed choices, hopefully the packages that arrive at our home will deliver fewer dangerous toxics for our dog and more healthy fun.

Struggling with a special needs puppy? Maybe a do-over will help.


Habib, R., & Becker, K. S. (2021). The Forever Dog: Surprising New Science to Help Your Canine Companion Live Younger, Healthier, and Longer. HarperCollins Publishers.

Nutrition, C. for F. S. and A. (2020). Phthalates. FDA.

Dobrzyńska, M. M. (2016). Phthalates—Widespread occurrence and the effect on male gametes. Part 2. The effects of phthalates on male gametes and on the offspring. Roczniki Panstwowego Zakladu Higieny, 67(3), 209–221.

Trasande, L., Liu, B., & Bao, W. (2021). Phthalates and attributable mortality: A population-based longitudinal cohort study and cost analysis. Environmental Pollution (Barking, Essex: 1987), 118021.

1. Makowska, K., Martín, J., Rychlik, A., Aparicio, I., Santos, J. L., Alonso, E., & Gonkowski, S. (2022). Biomonitoring parabens in dogs using fur sample analysis – Preliminary studies. Science of The Total Environment, 807, 150757.

Nutrition, C. for F. S. and A. (2020). Parabens in Cosmetics. FDA.

Craig, J. M. (2021). Additives in pet food: Are they safe? Journal of Small Animal Practice, 62(8), 624–635.

Mehdi Amin, M., Tabatabaeian, M., Chavoshani, A., Amjadi, E., Hashemi, M., Ebrahimpour, K., Klishadi, R., Khazaei, S., & Mansourian, M. (2019). Paraben Content in Adjacent Normal-malignant Breast Tissues from Women with Breast Cancer. Biomedical and Environmental Sciences, 32(12), 893–904.

Makowska, K., Martín, J., Rychlik, A., Aparicio, I., Santos, J. L., Alonso, E., & Gonkowski, S. (2021). Assessment of exposure to perfluoroalkyl substances (PFASs) in dogs by fur analysis. Environmental Pollution, 286, 117435.

Nutrition, C. for F. S. and A. (2020). Authorized Uses of PFAS in Food Contact Applications. FDA.…

Nutrition, C. for F. S. and A. (2021). FDA Issues Letter to Industry on Fluorinated Polyethylene Food Contact Containers. FDA.…

Potential health effects of PFAS chemicals | ATSDR. (2020, June 24).

Potential endocrine disrupting properties of toys for babies and infants. (n.d.). Retrieved October 18, 2021, from…

Harnett, K. G., Chin, A., & Schuh, S. M. (2021). BPA and BPA alternatives BPS, BPAF, and TMBPF, induce cytotoxicity and apoptosis in rat and human stem cells. Ecotoxicology and Environmental Safety, 216, 112210.

EWG’s Guide to Healthy Cleaning. (n.d.). Retrieved October 18, 2021, from

Harley, K. G., Calderon, L., Nolan, J. E. S., Maddalena, R., Russell, M., Roman, K., Mayo, -Burgos Stephanie, Cabrera, J., Morga, N., & Bradman, A. (n.d.). Changes in Latina Women’s Exposure to Cleaning Chemicals Associated with Switching from Conventional to “Green” Household Cleaning Products: The LUCIR Intervention Study. Environmental Health Perspectives, 129(9), 097001.

Sugita, K., Yamamoto, J., Kaneshima, K., Kitaoka-Saito, C., Sekimoto, M., Endo, O., Takagi, Y., & Kato-Yoshinaga, Y. (2021). Acrylamide in dog food. Fundamental Toxicological Sciences, 8(2), 49–52.