A dog licking a human’s hand.

Whether your dog is leaning in for a big slobbery kiss or your cat is insisting on drinking out of your water cup, it’s not uncommon to think, “Oh, it’s fine! Pets’ mouths are cleaner than our own.”

Is this somewhat prevalent belief true, though?

The short answer is “Maybe.” If you clean Fido’s mouth more than your own, then yes, they might have a cleaner mouth than you. However, if you’re not brushing your pet’s teeth multiple times a day, then it’s safe to say your pet does not have a cleaner mouth than you (assuming you do brush your own teeth regularly!). Unbrushed teeth are prone to bacteria buildup, and there could even be parasites hiding in your pet’s mouth.

Lower Bacteria Count, Higher Health Outcomes

We’re told that flossing and brushing our teeth twice a day will reduce the bacteria in our mouths, leading to healthier gums and teeth as well as fresher smelling breath. The same holds true for pets. Veterinarians agree that regularly brushing your pet’s teeth can reduce the overall number of bacteria in their mouths, helping to prevent periodontal disease and bad breath. Also, like with humans, not brushing your pet’s teeth could lead to heart, liver or kidney issues.

You can reduce bacteria by brushing your pet’s teeth at least once a day. Dog and cat toothbrushes as well as toothpaste can be found at your local pet store. Never reach for the human toothpaste when brushing your pet’s teeth. What may be safe for us is harmful to our pets.

Infectious Saliva and Open Wounds

Researchers have found that both humans and dogs have roughly 600 different types of bacteria in their mouths. Cats, on the other hand, have about 200 different types of bacteria in their mouths — and no, that does not mean cats have the cleanest of all mouths. Bacteria are still bacteria.

The types of bacteria in your pet’s mouth are dependent on the animal’s genetics, diet, lifestyle and hygiene habits. It’s important to remember that not all bacteria are bad — some are actually helpful. But too much bacteria, or bacteria that gets where it shouldn’t be, like in the bloodstream through scratches, licks or bites, isn’t good for anyone.

If you have any sort of open wound — a scratch, a small puncture from kitty teeth or anything like it — your first reaction should be to care for the wound before your pet can lick the spot in question. While hugs and kisses from your pet can bring comfort, their saliva can pass along diseases or cause an infection when they lick the punctured skin.

Capnocytophaga canimorsus is a common bacteria found in the mouths of both cats and dogs and serves as a good example of why you should heed this advice. If this bacteria strand is transmitted into an individual’s open wound AND they have a weakened immune system, the injury could become infected leading to sepsis or death if proper medical care is not sought. This is a rare occurrence – especially for people who have healthy immune systems – but nonetheless something to be aware of moving forward.

In the case of pets who live or play outside, you have the added possibility they could transfer parasites they picked up from putting dirt, feces or small animals in their mouth. You don’t want to introduce bacteria or parasites to that wound, so keep it clean and covered.

Just remember: If you have a wound and a pet licks it, immediately clean it out as best as you can — no matter your age or health. Then keep an eye on those wounds for any abnormalities so you can call your doctor and receive the care you might need.

Lastly, we should mention when a pet licks a wound that is already healing, their rough-textured tongue can damage your skin and reopen the sore. Take the right precautions and keep that healing wound away from your pet’s tongue.

Are Pet Kisses Dangerous, Then?

No, not necessarily! This article is not meant to make you nervous if Fido gives you a big kiss across the cheek. However, it does serve as a great reminder to brush your pet’s teeth and have caution in situations where their saliva can enter your bloodstream.

In addition to keeping your pet’s tongue away from open wounds, scientists and veterinarians say you shouldn’t encourage your pet to lick your mouth, nose and eyes. Those three spots on your face could be entry points for pathogens like E. coli into your bloodstream. So, it’s better to play it safe.


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The information in this blog has been developed with our veterinarian and is designed to help educate pet parents. If you have questions or concerns about your pet's health or nutrition, please talk with your veterinarian.