Are Dogs’ Mouths Cleaner Than Humans’?

For us dog lovers, it’s quite a disappointment to hear that the average dog’s mouth is not cleaner than the average human’s mouth. The good news is that dogs do not necessarily have dirtier mouths either. The comparison between two very different species is not so simple, but humans and dogs have this in common – the healthier the lifestyle, the healthier the mouth.

Microbes in Dogs’ Mouths

Dogs have an abundance of germs in their mouths but a dog-to-dog comparison would be more appropriate in quantifying the levels. One of the determining factors is the quality of the dog’s life. Is she always indoors? Is she a stray dog eating out of dumpsters? A well-cared-for dog will have a cleaner mouth than one who spends a substantial amount of time outdoors. Dogs left outside and unattended will eat plants, insects, and discarded food off the ground. Not only can they pick up all manners of microbes but they can also pick up parasites.

Why Do People Think Dogs Have Cleaner Mouths?

While dogs can pass some diseases on to us, we are probably more familiar with the diseases passed from human-to-human contact.  Consequently, we perceive dogs as having cleaner mouths. Humans can pass a variety of diseases to fellow humans via saliva and skin contact – hepatitis, herpes, and colds to name a few. Man’s best friend may not be known to commonly pass these illnesses to us via direct contact, but they can pass other infections, whether they are bacterial, viral, or parasitic.

People have passed around the rumor that dog bites are less infectious than human bites. There’s no conclusive evidence that either bite is more or less infectious than the other. It’s very much a case-by-case scenario. For example, a bite from a trash-eating dog has a higher risk of infection than a bite from a human who gets regular dental care. Additionally, the larger and deeper the bite, the higher the risk for infection.

Dental Diseases

Dogs suffer from dental diseases but they are not much different than humans in prevention or treatment options. It can be assumed that a dog who is not given a proper dental regimen will have a dirtier mouth and a dirtier mouth is a breeding ground for the bacteria that cause dental maladies.

Both humans and dogs commonly suffer from gum disease and both could have copious amounts of the bacteria that cause it if their teeth aren’t taken care of. While anecdotal evidence shows that small dogs have a higher frequency of gum disease than large dogs, the science isn’t conclusive on this. However, dogs seem to suffer less from tooth decay. This particular acid-loving bacterium that causes decay does not thrive as well in a dog’s mouth, which is more alkaline than a human’s mouth.

How to Keep Your Dog’s Mouth Clean

Feed your dog a high-quality, balanced diet. They should have sufficient calcium in their diet but too much calcium can cause bladder stones. You can buy dental chews or bully sticks in a variety of flavors but the calories can add up substantially.

Brush your dog’s teeth every day. If you can’t manage every day, try at least three to four times per week. Use dog toothpaste, but do not use a dog toothbrush. Use instead a super soft human toothbrush, or a baby toothbrush for small dogs. These are gentler on the gums than the ones made specifically for dogs – which I find are too overpriced but cheaply made.

Aim to have your dog’s teeth cleaned by a vet at least once per year. It is expensive because of the general anesthesia, but it will cost you less in the long run in terms of overall healthcare costs. The businesses that advertise cleaning without general anesthesia don’t clean as deeply and a conscious dog will be too stressed out during the procedure.

We can’t determine that a dog’s mouth is cleaner or dirtier than a human’s. We can say with absolute certainty that the standard of living for each individual dog or human has an impact on their oral hygiene. For many of us, the science is of no consequence. If you’re anything like me, you’d rather kiss your dog than most humans!

By Gabrielle Allemeier


Science Line: Is It Really True That a Dog’s Mouth Is Cleaner Than a Human Mouth?
Huffington Post: Whose Mouth Is Cleaner, Dogs or Humans?
Medical Daily: Did Your Dog Give You a Stomach Flu? Norovirus May Spread From Pets to Humans

About the Author
Gabrielle Allemeier volunteers her free time as an animal rescuer and foster pet parent. As an animal lover, she enjoys sharing the knowledge she has gained from her experience with a variety of animals. Along with being an animal lover, Gabrielle is a globetrotter. She lives in Los Angeles, California with her terrier, Thisbe.