Both dog and human mouths are hosts to hundreds of kinds of bacteria. The good news? Most of those bugs are species-specific, which means that Fido's germs won't survive long in your mouth, and vice versa. Still, because there's only about a 16 percent overlap of oral microorganisms between dogs and humans, so there's no such thing as comparable, objective "cleanliness" with regards to their mouths.
Have you ever heard that a dog's mouth is cleaner than a human mouth? Someone may have said this while their dog was passionately licking your face or eating off of your plate in a well-meaning attempt to make you feel better. Well, sorry: a dog's mouth contains just as much bacteria as your mouth does.
The Same, But Different
How To Stay Safe From Dog Germs
Watch And Learn: Our Favorite Content About Dogs
Should You Let A Dog Lick Your Face?
Share the knowledge!
Key Facts In This Video
Dog mouths are not cleaner than human mouths, as both mouths contain species-specific bacteria. 00:43
One 2015 study found that oral-to-oral transfer of bacteria from dogs to humans can cause gingivitis and periodontal disease. 01:14
You're more likely to catch an infection by swapping saliva with another human than with a dog. 02:37