Almost every owner knows the scene. You sit down on the sofa and your dog starts licking your hands. Some people melt; others wonder whether something is wrong. The answer is more interesting than it seems, and not always the one we expect.
Important note: this text is of a professional and informative nature and does not replace veterinary care. Every dog is an individual. At the slightest doubt, or at any sign of illness, always call your veterinarian.
Licking is not a single behaviour with a single meaning. It is a language with several meanings, and what your dog is actually saying depends on the context, its body language and its health.
Where licking begins
It begins in the first hours of life. The mother licks her newborns to stimulate breathing, elimination and circulation. So the very first touch a puppy experiences is a lick, and it is a touch that means survival and safety.
As puppies grow, they lick their mother's muzzle. They inherited this from wolves, where pups solicit food this way. That is the origin of the face and mouth licking dogs later direct at humans. It is no accident that many dogs go for the face first.
What a dog may be saying
Affection and bonding. This is the explanation closest to our hearts, and it is partly true. In 2015, Nagasawa and colleagues showed in Science that gentle contact and mutual gazing raise oxytocin, the bonding hormone, in both dog and human. The bond is not merely our imagination.
But I must be honest: that study measured gaze and contact, not licking. There is no evidence that licking itself triggers oxytocin. So it is more accurate to say licking is part of pleasant social contact from which bonding grows, rather than that licking is in itself a declaration of love.
Appeasement and a request for space. This is the meaning people most often miss. A brief lick of the nose or lips is one of the calming signals dogs use to defuse tension, their own or ours. Mariti and colleagues showed in 2017 that such signals do occur more often in situations of uncertainty and reduce the likelihood of conflict. If your dog licks you when you hug it or lean over it, it may not be expressing love but politely asking you to back off.
Taste and habit. Human skin is salty and scented, which is simply interesting to a dog. Licking is also often learned: the dog licks a hand, we smile and stroke it, and the behaviour is reinforced. This is logical and likely, though these two explanations lack dedicated research.
Does it matter where my dog licks me?
Here I must be candid, because a great deal is written online that nothing supports.
The face and mouth have the strongest explanation. This behaviour comes from a puppy's request to its mother and from greeting and appeasement behaviour. When your dog tries to lick your face as you come home, that is the closest thing to a greeting the canine tongue knows.
Hands are most likely taste and habit. Hands smell of everything we have touched, they are salty, and they are what we stroke the dog with.
Feet and toes are mainly a matter of scent, feet being the most odorous part of the human body. Something quite different is when a dog obsessively licks its own paws; that often signals allergy, skin inflammation or pain and belongs at the vet.
Ears are, between dogs, a sign of grooming and social bonding; dogs lick each other's ears and faces as mutual care.
Wounds are a chapter of their own. A dog licks a wound instinctively, and although saliva contains some antibacterial substances, licking introduces bacteria and slows healing. That is precisely why vets use collars.
So let it be clear: explanations along the lines of "hands mean this, ears mean that" are largely folklore. The only well-supported readings are face licking as greeting and appeasement, and self-directed licking as a possible sign of illness.
When licking becomes a warning
This is the most important part of this article, and many people do not know it.
If a dog suddenly begins licking floors, walls, furniture or objects excessively, this is often not a behavioural disorder but a sign of gastrointestinal disease. In 2012, Bécuwe-Bonnet and colleagues gave nineteen dogs with excessive surface licking a complete work-up, including ultrasound and endoscopy. In fourteen of the nineteen dogs — nearly three quarters — a gastrointestinal disorder was found. When the disease was treated, the licking disappeared or greatly diminished in most of them.
So a simple rule applies: if your dog suddenly starts licking surfaces or its own body excessively, it is not a whim. It is a sign that belongs at a veterinary examination. Nausea, reflux, pain or skin disease often hide behind it.
Is dog saliva dangerous to humans?
People rarely ask this, though they should. The answer is: usually not, but in certain circumstances yes.
The saliva of most healthy dogs contains the bacterium Capnocytophaga canimorsus. It can pass to humans not only through a bite but also by licking an open wound or mucous membrane. In rare individuals it can cause severe blood infection. The risk is greatest for people without a spleen, for the immunocompromised and for patients with liver disease. Infection is rare — van Dam and Jansz measured roughly 0.67 cases per million people per year in the Netherlands — but it can be very serious.
In practice this means: do not let a dog lick open wounds or broken skin, the faces of very small children, or people with weakened immunity. If a dog licks a wound, wash it, and see a doctor if redness or fever develop. This is no reason for fear, only for common sense.
So what should you do?
If your dog licks you moderately and is relaxed while doing it, this is part of its language and nothing needs changing. If it licks you every time you lean over it or hug it, ask yourself whether it is requesting more space. But if licking suddenly escalates, or turns to floors, objects or the dog's own body, do not delay a veterinary check.
A dog talks all the time. Licking is one of its words, and it is up to us to learn when it means hello, when it means politeness, and when it is a call for help.
Literature and sources
Bécuwe-Bonnet V, Bélanger M-C, Frank D, Parent J, Hélie P (2012). Gastrointestinal disorders in dogs with excessive licking of surfaces. Journal of Veterinary Behavior 7(4):194–204.
Nagasawa M, Mitsui S, En S et al. (2015). Oxytocin-gaze positive loop and the coevolution of human–dog bonds. Science 348(6232):333–336.
Mariti C, Falaschi C, Zilocchi M et al. (2017). Analysis of the intraspecific visual communication in the domestic dog: calming signals. Journal of Veterinary Behavior 18:49–55.
Firnkes A, Bartels A, Bidoli E, Erhard M (2017). Appeasement signals used by dogs during dog–human communication. Journal of Veterinary Behavior 19:35–44.
Rugaas T (2006). On Talking Terms with Dogs: Calming Signals, 2nd ed. Dogwise Publishing.
van Dam AP, Jansz A (2010). Capnocytophaga canimorsus infections in the Netherlands: a nationwide survey. Clinical Microbiology and Infection 17(2):312–315.
Note: interpretations of specific body parts are largely experiential rather than research-confirmed; this is flagged in the text.
This text is based on current professional knowledge and on our kennel's experience. It does not replace consultation with a veterinarian or cynologist.
