Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Dog germs
Name: Charles Cole
Age: N/A
Location: N/A
Country: N/A
Date: N/A 

Is a dog's mouth cleaner than a human's?

Charles, Indeed, I have heard that this is true, but I don't have any scientific report handy which confirms it. What I have heard in the past is that, on occasion, if someone is accidentally bitten by a person, the bite is considered quite serious.

If a study ever were done, I'm sure the actual 'cleanliness' of a human versus canine mouth would have to be compared based on a variety of normal foodstuffs consumed by each group (in the humans case, maybe hot dogs, cereal, soda, roast beef, etc) and the canines (dog food, garbage cans, various animal remnants found in the neighborhood). I'm sure you can see that there would certainly be occasions where the human's mouth would register as cleaner just because of what had been eaten earlier. Another house-kept dog, fed only purchased dog food and kept 'squeaky-clean' might register cleaner than perhaps a person with poor mouth hygiene. Since we humans regularly do floss and brush, and gargle, I am sure many of us do our best to try to 'keep up with Fido'. :)

I hope this information helps!

Thanks for using NEWTON!

Ric (rickru)

A possibility is that dogs' mouths are not "cleaner" at all, but that people bites are worse simply because the germs living in peoples' mouths are all germs that can attack you, whereas most of the germs living in a dog's mouth couldn't even if they got under your skin. They're *dog* germs, right? Specially adapted to living in dogs and not people. There aren't that many species of bacteria that can live in more than one species, although those that do are a real pain. Smallpox, you see, pretty much only lived in humans, so that when all humans were vaccinated the disease just died out. Tetanus, on the other hand, lives in cows as well as people, rabies lives in bats and raccoons, malaria in mosquitoes, plague in rats, etc. Since you can't take health care to the wild animals, you can't wipe out these diseases.

Christopher Grayce

Click here to return to the Biology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory