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Is A Dog’S Mouth Cleaner Than A Human’S Mouth?

At some point, all dog owners are exposed to their dog's saliva, either via friendly licks or bites. The idiom "a dog's mouth is cleaner than a human's" comes to mind immediately.

However, is this the case? Unfortunately, according to scientists and canine specialists, the answer is no. Dogs' lips and saliva have naturally high levels of germs.

Although they do not pose a threat to the animal, they may be hazardous to people if they come into touch with their blood.

Find out what these bacteria are, what hazards they pose to people, any exacerbating circumstances, and the best way to treat an infected wound in this article, "Is a Dog’s Mouth Cleaner Than a Human’s Mouth?" from BestForPets (bestforpets.org).

Why is canine saliva not cleaner than human saliva?

You are aware that your dog uses his tongue daily to communicate, investigate his surroundings, and lick himself. Licking is crucial for the animal since it contributes to its means of communication and comprehension. However, dogs prefer to lick several objects.

Consequently, canine saliva has an abundance of microorganisms. Obviously, every living organism has billions of bacteria, which contribute to health, digestion, and the maintenance of the immune system.

However, although some are used for the usual maintenance of your dog’s mouth and body, others may be harmful to people. Capnocytophaga canimorsus is the most well-known bacterium that can be hazardous to humans and is often found in the mouths of dogs.

It is naturally found in the saliva of dogs, cats, and people, and may cause serious infections in humans if it enters the circulation by a bite or wound-licking.

This bacteria poses no threat to the animal since it occurs naturally inside its body. However, when removed from this milieu, it poses a substantial danger and may transform into a pathogen.

Researchers have also discovered that dogs harbor Porphyromonas gulae bacterium, which may cause periodontal disease. Porphyromonas gingivalis is a strain of this bacterium unique to humans.

In addition, other Harvard researchers have identified over 615 distinct bacterial species in human lips, compared to about 600 in canine mouths. This tiny difference may have contributed to the notion that canine saliva is cleaner than human saliva, but comparing apples and oranges is like comparing apples and oranges.

This is because the lips of both dogs and humans are teeming with bacteria, yet these strains are distinct. In essence, a dog’s saliva is just as filthy as ours.

What Are the Possibilities of Contracting Diseases from a Dog's Kiss?

As humans, our skin forms a natural barrier against the great majority of viruses, bacteria, and germs of all types, protecting us from illness. With a wound, however, germs may enter the bloodstream and spread throughout the body.

Therefore, the dog may spread the disease to humans through a bite that breaks the skin, scratches that produce blood, or even a lick on an open wound. Pasteurella canis is the bacterium most usually detected in a dog’s mouth.

Additionally, as previously indicated, dogs may transfer the bacterium Capnocytophaga canimorsus via their bites, which can result in a serious bacterial illness in people. In addition, rabies is the most severe illness that dogs may spread via their saliva. 

On the other hand, a dog may consume Salmonella or E. coli-contaminated food, and these infections might be transmitted to people if they ingest the dog’s slime.

Exist Aggravating Components in Dog Saliva?

It seems that some conditions exacerbate the effects of exposure with specific microorganisms via a dog’s saliva:

  • Immunocompromised organisms are less able to protect themselves against external threats and are consequently more susceptible to bacterial infection.
  • Children under the age of five and older adults are more susceptible to illness.
  • Having wounds or lesions: Wounds and lesions are entry points for germs, which may then enter the bloodstream.

What to Do if You Believe You Have an Infection

In healthy persons, the chance of catching harmful germs from a dog’s saliva is rather minimal. However, if you are severely bitten or licked by a dog, you should immediately wash the lesion with clean water and soap to properly disinfect it. Then, seek medical care, regardless of how tiny the cut may seem.

Tips: To prevent any form of illness, properly wash your hands after contacting your dog, as well as the areas of your body (arms, legs, face) that he has licked. After such contact, refrain from contacting a kid, a vulnerable person, or food without first washing your hands. Lastly, prevent your dog from licking your face or any wounded skin.

How to Maintain Your Dog's Dental Hygiene

You cannot eliminate all germs from your dog’s mouth, but there are steps you can do to enhance his oral hygiene:

  • Brush your dog’s teeth a minimum of twice every week.
  • Utilize a toothpaste formulated to minimize plaque.
  • Feed the dog food designed to boost its oral health.
  • Offer dental treats that have been approved by the Veterinary Oral Health Council.
  • Schedule routine dental cleanings for your pet.


The microorganisms in your pet dog’s saliva are typically not dangerous to healthy humans, despite the fact that its cleanliness is undoubtedly inferior to your own. However, in certain instances it is possible to catch severe infections from dog saliva, but the risk remains modest.

However, it is preferable to avoid giving your dog large kisses and to sanitize your hands after each touch. However, as dog lovers, we at BestForPets (bestforpets.org) recognize that this is easier said than done, so this article, “Is a Dog’s Mouth Cleaner Than a Human’s Mouth?” was born!

Author Image

Dr. Deborah Fletcher

Deborah R. Fletcher, DVM, is a skilled veterinarian with more than 15 years of experience dealing with companion and exotic animals. She has experience caring for a variety of animals, including household cats and dogs, reptiles, birds of prey, and even primates. Dr. Fletcher is a valuable part of the BestForPets team, where she contributes to their aim of providing pets and their owners with the finest possible treatment and services.

Veterinarian (DVM) Dr. Deborah Fletcher


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