Dogster is reader-supported. When you buy via links on our site, we may earn a commission at no cost to you. Learn more.

Dog Health & Care

Are Dogs Mouths Cleaner Than Human Mouths? Vet Approved Facts & FAQ

Jessica Kim
By Jessica Kim · Reviewed & fact-checked by Dr. Alice Athow-Frost BVM BVSVet Approved
Dr. Alice Athow-Frost BVM BVS
Reviewed & Fact-Checked byDr. Alice Athow-Frost BVM BVSMRCVS (Veterinarian)
Alice, originally from London, became a small animal veterinarian after her 2016 graduation from the University of Nottingham in England. Her academic journey began at the University of Bristol where she studied Zoology, fueling her deep interest in all aspects of animal life.View authorThe information is current and up-to-date in accordance with the latest veterinarian research. Learn more
Updated on June 17, 2026
Share
Are Dogs Mouths Cleaner Than Human Mouths? Vet Approved Facts & FAQ

It’s commonly believed that dog mouths are cleaner than human mouths. However, this belief is simply a myth, and dog mouths aren’t any cleaner than human mouths. While there are some similarities between the two, there are just too many differences to make any fair comparisons. Some would say that it’s like comparing apples to oranges.

Since licking is a normal dog behavior, it’s worth understanding what’s going on inside your dog’s mouth. We’ll answer some common questions that many people have about dogs’ mouths and their oral hygiene.

divider dog paws 2 oct 2024

Comparing Dog Mouths and Human Mouths

While it may sound a bit gross, mouths are hosts to microbiomes and contain a diverse ecosystem of bacteria. Both human mouths and dog mouths contain billions of bacteria and can host roughly 700 unique species.1 Some species of bacteria found in the mouth of dogs are infectious to humans, but most are not.

There’s some overlap in the types of bacteria that are found in dog and human mouths. However, the majority of species found in a dog’s mouth are different from the species found in a human’s mouth. So, even though there are a few harmful bacteria that may occur in a dog’s mouth that would cause disease in a human e.g. Salmonella spp., most viruses and bacteria in a dog’s mouth can’t survive in a human host.

Image By: LanKS, Shutterstock

Origins of This Myth

It’s unclear as to how the myth about dogs having clean mouths came to exist. However, it’s possible that it started with the observation that humans don’t seem to catch diseases when their dogs lick them. While it’s common knowledge that diseases can be transferred orally from human to human, some people don’t realize that we can also catch diseases from their dogs. Oral transfer of harmful bacteria from dogs to their owners is rare, but it can still happen.

Dogs also frequently lick their wounds. So, it’s possible that people believed their saliva had healing properties. In fact, certain ancient civilizations, including the Greeks and Egyptians, included the use of dog saliva in healing rituals and practices.

Dogster divider_v2_NEW_MAY_24_

Frequently Asked Questions (FAQ)

Now that we’ve cleared up this myth, we’ll answer some frequently asked questions that many dog owners have about their dog’s saliva and oral hygiene.

Does Dog Saliva Have Healing Properties?

Technically, dog saliva and human saliva both contain healing properties. Histatins are proteins found in saliva, and they can help protect wounds from infections and encourage open wounds to close faster. Another protein found in saliva that can help speed up wound healing is nerve growth factor. Saliva also contains nitrite, which works to break down nitric oxide to prevent infections.

Should I Let My Dog Lick His Wounds?

While dog saliva may contain healing properties, it’s still best to take your dog to your veterinarian if they’ve sustained an injury. Your veterinarian can assess the wound and determine the best way to care for it and let it heal.

Dogs can lick wounds for a variety of reasons. Licking can help clean up any dirt or debris around the wound. Dogs may also lick their wounds to soothe any itching or inflammation. However, it’s not always a good idea to let dogs lick cuts and scratches. Dog saliva does have some healing properties but it also contains many bacteria that can cause infections. So, they can risk exacerbating a wound and make it worse if they continue licking a wound.

Image Credit: didesign021, Shutterstock

Can Infectious Diseases from a Dog’s Mouth Transfer to Humans?

Though the chances are low, dogs can still transfer infectious diseases when they lick a human. Since dogs and humans can host several of the same bacteria, dogs can cause humans to get sick if humans come in contact with their saliva.

One example of bacteria that can transfer from dogs to humans is Salmonella. Dogs that eat a raw food diet are at higher risk of ingesting contaminated meat. If they were to lick their owners after eating, the Salmonella bacteria could transfer to the humans, especially if the dog was licking their faces.

People have a higher risk of catching an infectious disease from dog saliva if the saliva enters their mouth or comes in contact with a cut or scratch on their skin. You can also catch an infectious disease from a dog bite. So, if anyone gets bitten by a dog, it’s important to clean the wound thoroughly and seek urgent medical attention.

Why Does My Skin React When My Dog Licks Me?

Some people will have an allergic reaction to dog saliva. Dog saliva contains certain proteins that can trigger a person’s allergies and cause their skin to develop a rash or break out in hives. Allergens can also be found in dog dander and urine.

Why Does My Dog’s Saliva Smell Bad?

A dog’s saliva can smell bad for a lot of reasons. Sometimes, it can simply be because they ate something stinky. However, smelly saliva and bad breath are usually indicators of an underlying health issue that requires veterinary care. For example, bad breath can be a sign of gum disease, kidney disease, or diabetes. Smelly saliva may also be caused by food or a foreign object getting lodged in your dog’s mouth.

Image Credit: Alexas_Fotos, Pixabay

How Can I Keep My Dog’s Mouth Clean?

Dental disease is prevalent in dogs, and 80% of dogs over 3 years old have active dental disease. So, it’s important to establish a dental care routine as early as possible and be vigilant about keeping your dog’s mouth clean.

One of the most effective ways to keep your dog’s mouth clean is to brush their teeth daily. Most dogs won’t enjoy getting their teeth brushed at first and will require gradual training to get used to the feeling. It’s also best to try out different types of brushes to see which ones are most comfortable for your dog.

Dog mouthwashes and water additives are other dental products that you can add to your dog’s dental hygiene routine. They’re not as effective as toothbrushing, but they’re still good at freshening up your dog’s breath. Dental chews can also help keep plaque and tartar buildup at bay.

Lastly, make sure to stay on top of your dog’s routine physical exams. Your veterinarian can examine your dog’s teeth and recommend and perform dental cleanings, if necessary.

If you have any concerns about your dog or their health, we recommend you contact your vet directly.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's our online service where you can talk to a vet online and get the advice you need for your dog — all at an affordable price!

PangoVet_Mention-in-Content Savings V1


divider dog paws 2 oct 2024

Conclusion

Dog mouths aren’t any cleaner than human mouths, and their saliva can have both positive and negative effects on wound healing.  So, it’s best to take your dog to your veterinarian if they sustain an injury and have an open wound. Your veterinarian can work to protect the wound and prevent it from getting infected.

You also can’t rely on your dog’s saliva to keep their mouth and teeth clean. Dogs require daily care to prevent dental disease. Making it a habit to brush your dog’s teeth and using other dental hygiene products can lower the risk of dental disease significantly and ensure your dog’s teeth stay healthier for longer.


Featured Image Credit: Bachkova Natalia, Shutterstock

Want content like this delivered to you?

News, insights, expert advice, and everything dog

Jessica Kim
Authored by

Jessica Kim

6 Quick Fixes When You're Out of Dog Shampoo

6 Quick Fixes When You're Out of Dog Shampoo

You’re staring at a muddy pup… and an empty bottle of dog shampoo. Now what? Take a breath, and don’t panic! Your bathroom and kitchen might be hiding some sur…

Dan Seymour
By Dan Seymour · 8 months ago
From Breeders to Your Door: How PuppySpot Safely Delivers Healthy Puppies Nationwide

From Breeders to Your Door: How PuppySpot Safely Delivers Healthy Puppies Nationwide

Bringing a puppy into your home is a life-changing decision, one that deserves thought and care right from the moment you begin looking for one. With so many o…

Nicole Cosgrove
By Nicole Cosgrove · 8 months ago
When Do Puppies Start Walking? Early Development Explained (Vet-Verified)

When Do Puppies Start Walking? Early Development Explained (Vet-Verified)

Watching puppies grow up is delightful, as puppyhood is a time of challenges, curiosity, and fun. Not only are puppies adorable, but watching them learn how to…

Misty Layne
By Misty Layne · 10 years ago
12 Signs of Aging in Dogs: Vet-Verified Changes to Look For

12 Signs of Aging in Dogs: Vet-Verified Changes to Look For

This article has been reviewed by a qualified veterinarian using information available at the time of review. The knowledge of canine medicine is continually e…

Kit Copson
By Kit Copson · 10 years ago
Why I Created Chi Dog: Whole Food Nutrition That Supports Dogs From the Inside Out
June 16, 2026

After more than 15 years practicing as an integrative veterinarian, I saw the same pattern over and over again. Dogs were struggling with skin allergies, chron…

Dr. Susan Bohrer DVM, CVA
By Dr. Susan Bohrer DVM, CVA
Better Than Kibble and Just as Easy to Feed
June 15, 2026

There is a reason kibble is such a popular choice for dog food. This diet option is incredibly easy to purchase, store, and feed. Unlike many fresh and raw foo…

Sara Seitz
By Sara Seitz
The Dogster Magazine is Officially Back!
June 12, 2026

The Dogster Magazine relaunch is officially underway with a fresh new look and an all-new digital experience. We're thrilled to reintroduce the Dogster communi…

Dogster Team
By Dogster Team
The Organization Helping Pets Feel Safer, Happier, and ‘Fear Free’ - Heroes of the Pet World
June 12, 2026

For many pet owners, stress during veterinary visits, grooming appointments, travel, or even routine handling can feel like an unavoidable part of life with an…

Nicole Cosgrove
By Nicole Cosgrove

Love Dogs? So Do We! Join the Dogster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.

You may opt-out at any time. View our Privacy Policy for more information.

The Dogster app on a phone