Why do dogs lick their lips?

Lip-licking is one of those small, everyday behaviors dogs do that can mean very different things depending on context. As a clinician who watches a lot of dog–human interactions, I find that learning the range of meanings behind a dog’s quick tongue flick can help owners make better choices about care, training, and when to call the veterinarian.

Why lip-licking deserves attention from every dog owner

Noticing lip-licking in ordinary situations — at the food bowl, when guests arrive, during car rides, or in the vet’s waiting room — gives you a nonverbal window into your dog’s state. In my experience people often notice lip-licking and interpret it only as hunger or “cute” behavior, but that same movement can also be a sign of stress, nausea, or oral pain. Misreading the signal can lead to responses that make the problem worse: comforting a dog who is licking out of anxiety may reinforce the association between attention and stress, while ignoring persistent lip-licking that is due to a mouth injury delays veterinary care.

When you start to place lip-licking in context — who’s present, what happened right before, whether the dog is eating — you gain useful information for decisions about training, environment changes, and welfare. That helps you meet needs more accurately and strengthens trust between you and your dog.

Bottom line — the short takeaway about lip-licking

At a glance, dogs lick their lips for several common reasons: as a social signal (appeasement or avoidance), to sample or express interest in a smell or taste, because of nausea or gastrointestinal upset, to groom and clear the mouth, or in response to stress. A single lick here and there is normal; persistent or escalating licking that lasts hours to days, or that appears with other signs such as drooling, vomiting, or behavioral withdrawal, is more concerning.

Quick cues to decide whether you should act: if the licking comes with yawning, avoidance, tense body language, or trembling, it may suggest stress; if it follows travel or precedes vomiting it may indicate nausea; if there’s bad breath, blood, or an obvious sore it points to an oral problem. If you aren’t sure, observing and recording a short video to show your veterinarian is often very helpful.

What lip-licking communicates: signals and the biology behind them

Dogs use subtle body language to communicate and lip-licking is often part of that repertoire. In social contexts a deliberate lick toward another dog or person may be an appeasement or calming gesture — a way to reduce tension and avoid escalation. I typically see this in shelters and vet clinics where dogs are uncertain about new people or other dogs: the lick is accompanied by a softening in the eyes and a turned head.

Biologically, licking the lips also spreads saliva across the muzzle and may help a dog sample scents and tastes. Saliva carries dissolved odorants from food particles or interesting surfaces to the vomeronasal organ and nose, so the behavior can reflect sensory exploration. Grooming is another simple function: when food particles or grit collect around the mouth, a dog will lick to clean the area.

Finally, lip-licking can be a reflexive response to nausea or gastrointestinal discomfort. Excessive swallowing, retching motions, and repeated licking of the lips or lips and chops can appear before vomiting or when a dog feels queasy from motion, medication, or stomach upset.

Everyday triggers — when dogs are most likely to lick their lips

Understanding triggers helps you interpret what lip-licking probably means in a given moment. Food-related triggers are obvious: the sight or smell of a meal, the anticipation of a treat, or even tasting residue after eating will provoke licking. I often see intense anticipatory licking when owners have an inconsistent feeding routine or use food as a primary attention-getter.

Social or environmental stressors also trigger lip-licking. New people, noisy households, crowded dog parks, vet visits, or the approach of an unfamiliar dog can produce quick licks as a dog tries to defuse tension or signal non-aggression. Motion sickness, certain medications, or recent vomiting commonly precede sustained licking and smacking of lips. Other physical triggers include heat (dogs may lick if their mouths feel dry), dental pain or oral irritation from foreign bodies, and chemical irritants like household cleaners or plants.

Warning signs to watch for: when lip-licking could indicate illness

Some patterns should prompt a call to your veterinarian. Persistent licking that continues for days, increases in frequency, or appears without clear situational triggers can be a sign of medical issues. When lip-licking occurs with drooling, repeated vomiting, lethargy, loss of appetite, or a change in drinking, treat it as potentially medical rather than behavioral.

Check the mouth for swelling, broken or loose teeth, ulcers, foul odor, or bleeding; any of these findings should lead to prompt veterinary assessment. Neurological signs such as disorientation, circling, head tilt, or seizures combined with abnormal mouth movements or licking may indicate a more serious condition affecting the brain or cranial nerves and warrant urgent evaluation.

How to respond — a clear checklist for concerned owners

1. Observe and note the context: When did the licking start? What happened just before? How long does it last? Video a typical episode if you can.
2. Look for other signs: Is the dog eating normally, energetic, or quieter than usual? Any drooling, vomiting, bad breath, bleeding, or swelling around the mouth?
3. Check the mouth gently: Use calm restraint and a soft voice. Look for obvious foreign objects, broken teeth, swelling, or a smell that’s worse than normal. Don’t force the mouth open if the dog resists; seek professional help instead.
4. Remove or reduce obvious triggers: Move to a quieter room if stress-related, avoid immediate feeding if the dog feels nauseous, and stop using household products that could irritate the mouth.
5. Apply calming measures: Sit with the dog at their level, offer predictable, low-arousal attention, and delay high-value treats that may increase anticipatory licking.
6. Contact your veterinarian if the behavior persists, worsens, or is accompanied by the red flags described above. Provide your notes and any video — it helps the clinic prioritize and plan the exam.

Training strategies to reduce unwanted lip-licking

When lip-licking stems from anxiety or attention-seeking rather than medical causes, targeted training and management can reduce it. Desensitization and counterconditioning are practical approaches: break the trigger into small, manageable steps and pair neutral or mildly stressful steps with predictable, low-key rewards so the dog’s association changes over time. For example, if the doorbell triggers licking, start with the sound played softly and reward calm behavior, gradually increasing the sound as the dog remains comfortable.

Reinforce calm behavior rather than the licking itself. If a dog licks and receives immediate attention, the licking can be unintentionally shaped into an attention-seeking behavior. Instead, wait for a pause in licking or other signs of relaxation before giving attention or a treat. Predictable routines — consistent feeding times, regular walks, and a stable daily schedule — also reduce anticipatory anxiety and the licking that comes with it.

Adjust feeding methods to reduce fast or anticipatory consumption: use puzzle feeders, scatter feeding in the yard, or a slow-feed bowl to change the pattern of food excitement. In many cases these simple environmental changes decrease the frequency of lip-licking linked to meal anticipation.

Helpful gear and tools owners can use safely

• Puzzle feeders and slow-feed bowls: these slow intake and lower intense anticipatory licking around mealtimes.
• Calming supports: dog-appeasing pheromone diffusers, anxiety wraps, or white-noise machines can reduce environmental stress when used appropriately and under guidance from your veterinarian or behaviorist.
• Oral-care tools: a soft dog toothbrush, veterinary toothpaste, and veterinarian-recommended dental chews help reduce mouth disease that can cause licking.
• Pet first-aid supplies: clean gauze, a flashlight to inspect the mouth, and a phone ready to video episodes for your vet. Avoid administering human pain medications; always consult your veterinarian.

References and sources for further reading

• Merck Veterinary Manual: “Nausea and Vomiting in Small Animals” — Merck Veterinary Manual online chapter on canine vomiting and nausea.
• American Veterinary Medical Association (AVMA): “Fear and Anxiety in Dogs” — AVMA client information on recognizing and managing fear behaviors in dogs.
• American College of Veterinary Behaviorists: “Position Statement on Fear, Anxiety, and Phobias in Dogs” — clinical guidance from ACVB on behavior assessment and treatment planning.
• Beerda, B., Schilder, M. B. H., van Hooff, J. A. R. A. M., de Vries, H. W., & Mol, J. A. (1998). Behavioral and physiological indicators of stress in dogs. Physiology & Behavior, 64(3), 509–516.
• Overall, K. L. (2013). Clinical Behavioral Medicine for Small Animals. Elsevier — comprehensive clinical reference on canine behavior assessment and interventions.