Is A Dog’s Mouth Cleaner Than Humans?

is a dog's mouth cleaner than humans


If you own a dog, you probably love getting kisses and licks from your pet. You probably do not worry about this because you have heard the saying that a dog's mouth is cleaner than a human mouth.  

Is this true?  

The simple answer is no. This is not true.

Where Did The Saying Come From?

People believed a dog's mouth is cleaner than a human one because they saw dogs licking their wounds. They noticed that this promoted healing. 

People came to believe that dog saliva had healing properties. The Ancient Greeks and Egyptians used dog saliva in healing, and dogs became a part of their religious healing rites.

While saliva does have some antibacterial properties due to certain proteins that can ward off infection, licking wounds removes dead tissue and debris, and this is the more likely reason for wound healing. Sometimes over-licking can cause trauma to the wound.

Many believed the saying was true because it is relatively rare for humans to catch illnesses

from dogs. For example, most upper respiratory tract infections in humans are caused by viruses, and these are usually species-specific.

People also used to think that a dog's mouth was cleaner because they believed human bites were more likely to become infected than dog bites.  Research has shown this not to be true. Bites from a human (other than on the hand) have no more infection risk than from any other animal bite. 

What Is In Your Dog's Mouth?

There are over 600 types of bacteria in human mouths. Dogs' mouths have about the same. The bacteria are responsible for what is known as "morning breath" in humans, and "dog's breath".

Only about fifteen percent of these bacteria are identical. It is like comparing apples with oranges when comparing dog and human mouths to see whether a dog's mouth is cleaner than a human mouth.  

An example is a bacterial family - porphyromonas - that causes periodontal disease in both humans and dogs. A human's mouth contains one of the porphyromonas called P. gingivalis, while dogs' have P. gulae. 

The types of bacteria in dogs' mouths depends on various things, including diet, environment, oral hygiene, and genetics.

As well as bacteria, some parasites live in your pet's saliva. 

What Bacteria In A Dog's Mouth Causes Disease In Humans?

The main thing to minimize the risk of infection is to reduce the opportunity for your pet's bacteria to get through your skin.

If you let your dog lick your wounds or if your furry friend bites you, you might get the pasteurella bacteria. This usually lives in your dog's mouth, but can cause skin and lymph node infections in humans.  

Your pet's feces may contain salmonella, e.coli, clostridia, and Campylobacter, which are bacteria living in your dog's gut. These can cause serious intestinal disease in humans. You can get these bacteria from touching your mouth after your hands have come into contact with your dog's fecal matter. If you mainly feed your dog raw food, your pet will have a greater risk of getting salmonella which can be passed on to you. If you own a cat and your dog gets into the litter tray, your dog could pick up bacteria from the cat's poop, which can cause you an infection.

Dogs carry the bacteria bartonella henselae, which they can pick up by eating the feces of infected fleas, ticks and lice. It is not yet certain whether dogs can pass infection related to this bacteria to humans, although this can occur through cats. 

In about ten to fifteen percent of cases, infection will occur when a dog bites a human.

Can Dog Parasites Make Me Sick?

If your dog licks his backside, and then your face, you could possible get parasites.   

However, the parasite eggs need to have matured to infect you, so the chance of you getting an infection is small. 

There are two parasites, giardia, and cryptosporidium, which do not require the eggs to have matured to transmit infection. You could get these if your dog licks your face.   

How Does My Dog's Mouth Become Dirty?

Dogs' mouths are used regularly for all types of things. They will use it to pick up toys, eat and drink, clean themselves, show affection, lick their wounds, clean their coat or skin, carry things they have dug up in the garden, and so on. Few of the things your pet will carry in its mouth will be clean, and so your pet's mouth will pick up bacteria.

Is It OK For My Dog To Kiss Or Lick Me?

One lick or kiss from your dog can put millions of bacteria on your face or body. Fortunately, most people do not get ill from this.

Some people are more vulnerable to infection, such as those with a poor immune system. Very old or very young people may be more susceptible, along with those undergoing cancer treatment. If you have a wound or cut on your face, you may have a greater risk of infection if your dog licks or kisses you.

There are various ways to minimize the risk of infection:

  • Make sure your dog has regular tick and flea treatments.
  • Thoroughly wash your hands after cleaning up your dog's feces or patting your pet.
  • Pick up your dog's feces regularly from your yard
  • Wash, disinfect or replace household items your dog regularly picks up or lies on
  • Prevent your dog from licking your wounds
  • Minimize, or stop, your pet kissing or licking your face where possible
  • If a dog bites or scratches you, see a doctor as soon as possible especially the wound is deep
  • Ask your vet to worm your dog regularly and do a fecal exam
  • Keep your dog away from the trash can and any rancid food.
  • Avoid your dog coming into contact with wild animals.

How Can I Keep My Dog's Mouth Cleaner?

Like a human's mouth, a dog's mouth may suffer from various problems such as tooth decay, bad breath, and periodontal disease. Good oral routines can help ensure your pet's mouth is cleaner and reduce harmful bacteria.  

If you get your pet as a puppy, brush his teeth each day. He will come to accept this as part of his daily routine as he grows up. If you got your pet later in his life, ask your vet how best to start brushing his teeth so that he enjoys it.

Use dog toothpaste, not human toothpaste, which can be harmful. Ask your vet to do a dental clean when your dog goes for his regular checkup. 

Good oral care can minimize gum disease in dogs. This type of infection can lead to difficulty eating, and your pet might not get the nutrients he needs. This can be made worse if your dog loses teeth through rotting or extraction. Small and older dogs are at greater risk of gum disease, so good oral care is even more important for them.