Should You Let Your Dog Lick Your Face?

Your dog licks your face. Someone nearby says “dog mouths are cleaner than human mouths.” Someone else looks horrified. Who’s right?

Neither, really. The question isn’t whether dog mouths are clean or dirty. It’s whether anything in dog saliva poses a meaningful health risk to you specifically.

The “Cleaner Than Human Mouths” Myth

This claim has been circulating since at least the 1990s and needs to die. Here’s why it’s wrong:

Dog mouths and human mouths contain roughly the same number of bacteria, approximately 600 to 800 species. But the species composition is largely different. A 2015 study in the Archives of Oral Biology found that only about 16% of bacterial species overlap between dog and human mouths.

The comparison is meaningless because “clean” isn’t measured by total bacteria count. It’s measured by whether the bacteria present are harmful to you. Dog mouths contain bacteria that are harmless to dogs but potentially problematic for humans, and vice versa.

What’s Actually in Dog Saliva

Bacteria

Dog mouths harbor several bacteria that can cause infection in humans through open wounds or mucous membranes:

• Pasteurella is found in the mouths of 50 to 75% of dogs. It can cause skin infections, cellulitis, and in rare cases, sepsis if it enters the bloodstream through a wound.
• Capnocytophaga canimorsus is the one that makes headlines. It’s present in most dog mouths and is usually harmless, but in immunocompromised individuals, it can cause sepsis that progresses rapidly. Fatal cases exist but are extremely rare.
• MRSA (Methicillin-resistant Staphylococcus aureus) can pass between dogs and humans in both directions. Dogs can carry MRSA without symptoms.

Proteins

Dog saliva contains proteins that trigger allergic reactions in sensitive individuals. The main allergen is Can f 1, produced in the salivary glands. If you’re allergic to dogs, the saliva is actually a bigger trigger than the fur.

Parasites (Indirect)

Dogs that eat raw meat, feces, or dead animals can carry parasite eggs in their mouth. Roundworm (Toxocara), hookworm, and Giardia cysts can theoretically transfer through licking, though this route of transmission is less common than direct fecal contact.

Risk Assessment: Who Should Avoid Dog Licks

Low Risk (Healthy Adults)

For a healthy adult with no open wounds on their face, a dog lick is statistically harmless. Your intact skin is an effective barrier against the bacteria in dog saliva. The mucous membranes of your mouth, nose, and eyes are less protected, but the immune system of a healthy adult typically handles incidental exposure without issue.

The risk isn’t zero, but it’s in the same category as other daily exposures you don’t think about: touching a shopping cart handle, using a public restroom, or eating at a restaurant.

Higher Risk (Should Avoid Mouth and Eye Contact)

• Immunocompromised individuals (HIV/AIDS, chemotherapy, organ transplant recipients on immunosuppressants). Capnocytophaga and Pasteurella infections that a healthy immune system handles easily can become serious in these populations.
• Infants and children under 5. Their immune systems are still developing, and they’re more likely to put their hands in their mouths after being licked.
• People with open wounds, eczemas, or active skin conditions on the face. Broken skin bypasses the primary barrier.
• Elderly individuals with compromised immune function.

The Open Wound Rule

This is the real concern. Dog saliva on intact skin is generally fine. Dog saliva in an open wound is a legitimate infection risk. A dog licking a cut, surgical incision, or cracked skin introduces Pasteurella and other bacteria directly past the skin barrier. If a dog licks an open wound, clean it thoroughly with soap and water and watch for signs of infection (redness, swelling, warmth, pus).

What About the Healing Claims?

You’ve probably heard that dog saliva has healing properties. There’s a kernel of truth here. Dog saliva contains some antibacterial compounds (lysozyme, peroxidase) and growth factors that promote cell migration. Studies in rodents have shown that saliva application can accelerate wound closure under controlled laboratory conditions.

In the real world, these benefits are far outweighed by the bacterial load in the saliva. A dog licking a wound introduces more pathogens than the antibacterial compounds can neutralize. This is why veterinary cones (the cone of shame) exist: to prevent dogs from licking their own surgical sites, because it causes more infections than it prevents.

Why Do Dogs Lick Faces?

Understanding the behavior helps contextualize it:

• Social greeting. Wolf pups lick the mouths of adult wolves returning from a hunt, likely to stimulate regurgitation of food. Domestic dogs retain this as an affectionate greeting gesture.
• Taste. Human skin tastes salty. Post-workout or on a hot day, your face is essentially a salt lick.
• Attention-seeking. If face licking gets a reaction (laughter, pushing away, talking to the dog), it’s reinforced.
• Submission/appeasement. Dogs lick the faces of individuals they perceive as higher status. It’s the canine equivalent of a respectful nod.

The Practical Answer

If you’re a healthy adult and your dog is healthy, vaccinated, dewormed, and doesn’t eat raw prey or feces, occasional face licking is unlikely to harm you. The risk is real but extremely low for a healthy person with intact skin.

If you or someone in your household is immunocompromised, very young, very old, or has open facial wounds, redirect the licking to hands (which you can wash easily) rather than face, mouth, and eyes.

Washing your face or hands after dog licking is the simplest risk reduction measure. It doesn’t need to be immediate or anxious, just routine.

Frequently Asked Questions

Should I stop my dog from licking my baby’s face?

Yes. Babies have developing immune systems, frequently rub their eyes and mouth, and can’t wash their own hands. Redirect the dog to licking the baby’s feet (enclosed in socks) or teach the dog an alternative greeting behavior. Supervise all dog-baby interactions regardless.

My dog licks their own butt and then licks my face. How bad is that?

It’s as unpleasant as it sounds. Fecal bacteria, including E. coli and potentially parasite eggs, transfer through this route. If your dog is a dedicated self-groomer, keeping them on a regular deworming schedule and redirecting face licking reduces (but doesn’t eliminate) the risk.

I’ve been letting my dog lick my face for years with no problems. Am I just lucky?

Probably not lucky, just healthy. An intact immune system handles the bacterial exposure from dog saliva without noticeable issue in the vast majority of cases. The risk exists but manifests primarily in people with compromised barriers (immune system, skin integrity).