Do Dogs Have Cleaner Mouths Than People?

According to popular belief, a dog’s mouth is cleaner than a person’s. But is this really true?

Well, that depends. Cleanliness is really a discussion about the amount and type of bacteria the mouth contains. And that amount is determined by what was recently in the mouth. Unlike humans, dogs enjoy raw meat, garbage, and animals in varying states of decomposition.

If Fido just nabbed himself a nice decaying squirrel carcass, we could easily come to the conclusion that, no—his mouth is not cleaner than ours. Since Fido could have picked up disease causing germs from the dead animal it is possible that he might pass on these dangerous germs to humans in a bite.

However, germs for the most part are species specific. What that equates to is this: Harmful dog germs are usually harmless for humans, unless we are talking about rabies. This disease affects both dogs and humans in equally damaging ways. By the same token, human germs probably won’t harm a dog.

Now, human germs can harm humans. So a mouth full of harmful human bacteria would affect a person far more than a mouth full of doggie bacteria. So you might be better off kissing a dog than a human.

In an October 2005 story on ABC’s 20/20, Dr. Marty Becker, veterinarian and author of Chicken Soup for the Dog Lover’s Soul , commented on the theory that dogs’ saliva had some sort of germ-fighting ability. In the interview he stated that it isn’t the antibacterial property in the saliva that supports healing but rather the dog’s tongue removes infected tissue and stimulates circulation.

Becker reiterated that staph, strep and rhinoviruses do not generally carry back and forth between species. He also concluded that as long as your dog is vaccinated against rabies and kept free of parasites, a wet slurp on the cheek probably won’t do you any harm. In fact, it will probably do you a lot of good.

As Dr. Becker so aptly put it, “They love us conditionally, they make us laugh. If we’re going to give them a little kiss to thank them for that, then that’s good by me.”