Dog Smacking Lips In The Middle Of The Night? 7 Surprising Causes

In the middle of your deep, contented sleep, you suddenly hear a strange noise coming from beside your bed.

Perturbed, you investigate the noise- and find out that it’s your dog smacking its lips that has been the cause of the commotion.

“Why is my dog smacking its lips in the middle of the night?” you may wonder.

In the most harmless cases your dog may simply be dreaming about food, causing them to smack their lips during sleep.

Constant smacking or licking of lips can act as an instinctual calming behavior that helps your dog relax, but it can also signify a poor or irregular diet.

Some other common causes of lip smacking include:

  • Dehydration
  • Nausea
  • Reinforced behavior
  • Emotional distress
  • Cognitive dysfunction
  • Seizures
  • Oro-Dental problems

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Why Is My Dog Licking Her Lips All The Time?

Why Is My Dog Licking Her Lips All The Time?

Dogs lick and smack their lips for many reasons as it can be a form of communication.

For example, the action can be used to convey messages of appeasement when they are confronted by aggressive dogs or disgruntled owners.

Dogs may also lick their lips more often if there is always food around. Smelling the food and becoming hungry may naturally induce the production of saliva, and as a result your dog may lick its lips to prevent its drool from dripping all over the place.

On the other hand, if your dog had tasted something toxic, bitter or downright disgusting (like Catchmaster glue traps!), they may also lick their lips in an attempt to remove the taste from their mouth.

In rare cases, the licking and smacking behavior can be a personal quirk. In other words, lip licking or lip smacking could be an unusual behavior that has developed naturally, but which has no particularly harmful effects.

Other potential explanations for why your dog might be acting this way can include dehydration, digestive problems, cognitive issues, and oro-dental conditions.



Dogs can become dehydrated quite easily, especially when the weather gets cooler, hotter or drier.

If your dog suffers from medical conditions such as liver or kidney disease they can lose water a lot faster- or may not retain water as efficiently- as a healthy dog.

Dogs that are dehydrated may smack or lick their lips excessively to wet their oral region as a dry mouth can be uncomfortable.

Some signs that indicate that your dog is dehydrated include:

Rehydrate your dog by ensuring there is always sufficient water for them to drink.

Frequently switch out old water with new, fresh water. It would also help if your dog wasn’t scared of its water bowl!

Providing wet foods is also an excellent choice to boost your dog’s liquid uptake whilst maintaining a healthy and balanced diet. A recommended option is the Pedigree Packs of Wet Dog Food made in the USA with a rating of 4.7/5 from over 11,400+ satisfied customers on Amazon. 

In severe cases of dehydration, you may need to bring your dog to the vet for IV fluid therapy.



Nausea causes excess production of saliva in dogs as their body prepares to protect the surfaces of organs from acidic bile. This can make the dog lick and smack their lips to remove the excess saliva.

Causes of nausea often involve GI issues such as food allergies, acid reflux, pancreatitis, and inflammatory bowel disease.

Hunger is also a prominent cause of nausea, as the accumulation of gastric acid in an empty stomach can lead to the movement of these fluids into the esophagus.

This can produce an irritating sensation in the throat and mouth, making your dog reactively lick their lips, hiccup, and swallow in an attempt to resolve the irritation.

Signs of nausea can include:

To prevent hunger-induced nausea in the middle of the night, you can provide a light, late-evening snack. Suitable foods are ones that are easy to digest, such as chicken breast, potatoes and bananas.

Antacids such as Pepto-Bismol may also help to relieve nausea and acid reflux. The proper dosage of Pepto-Bismol for dogs is 1 teaspoon for every 10 pounds of body weight, every 6 hours.

If your dog continues to experience nausea or associated symptoms over consecutive days, it would be best to consult with a vet.

Reinforced Behavior

Reinforced Behavior

Over time, your dog may have realized that licking or smacking their lips results in being positively rewarded with your attention. As a result, the strange behavior continues.

If reinforced behavior is indeed the cause, each time that you give attention to your dog further encourages them to lick or smack their lips over and over again.

In order to stop the cycle of unwanted dog lip-smacking behavior, you will need to ignore your dog when it begins licking or smacking so that its habits can become reconditioned.

However, try not to punish them as this can increase emotional distress and actually further worsen the behavior.

A good idea would be to seek advice from a dog behaviorist, as they may be able to provide the appropriate training methods necessary to curb this unwanted action.

Emotional Distress

Emotional Distress

When dogs feel uncomfortable, they may lick or smack their licks to show their confusion or fear.

For dogs, feelings of fear, anxiety or stress can be caused by events ranging from thunderstorms, to being petted by strangers, to hearing foreign sounds.

Other signs of emotional distress can include:

  • Tenseness
  • Crouched position
  • Lowered ears with a tucked tail
  • Avoidance of eye contact

To help reduce your dog’s emotional distress, you can:

  • Provide more daily exercise
  • Redirect their attention by providing interactive toys
  • Ignore stressful behaviors where possible
  • Reward calmness
  • Introduce new environments
  • Removing any sources of distress
  • Give your dog some space.

In severe cases of emotional distress, consult with your vet as he may be able to prescribe medication or refer you to a dog behaviorist to recondition your pup’s fears.

Cognitive Dysfunction

Cognitive Dysfunction

Canine cognitive dysfunction syndrome is a condition which describes a change in neural networks, causing the development of abnormal behavior. This may also be an explanation as to why your dog smacks or licks its lips randomly and excessively.

Similar to dementia in humans, the syndrome commonly develops amongst senior dogs.

Other symptoms of the condition can include:

While unfortunately there is no cure for this condition, you can delay its effects by ensuring your dog has a healthy diet and making sure they have regular physical and mental stimulation.

What’s The Best Dog Puzzle For Mental Stimulation?

What's The Best Dog Puzzle For Mental Stimulation?

Finding a suitable puzzle for delaying canine cognitive dysfunction can be difficult. However, I have personally found Outward Hound interactive dog puzzles to be exemplary in this regard.

An excellent product to strengthen neural circuits, promote mental development and limit destructive behavior is the Fun Feeder Slow Bowl.

The bowl will also slow down your dog’s eating habits, reducing the chance of bloating and indigestion.

The interactive puzzle has several other positive qualities, including:

  • PVC-free, BPA-free and phthalate-free
  • Non-slip base to prevent floor damage
  • Produces minimal sound on hard floors
  • Easily cleaned with water and soap

With a 4.7 out of 5 star rating on Amazon from over 53,500+ global customers, Outward Hound’s fun feeder slow bowl is an excellent option for increasing mental capability and delaying cognitive dysfunction!

To opt for a more difficult puzzle, you can check out other highly acclaimed products by Outward Hound. There are a range of dog puzzles with different levels of complexity such as:


Seizures can randomly activate neural circuits, causing the involuntary movement of certain body parts.

If your dog experiences even a partial seizure, the abnormal activation of the muscles controlling the tongue can cause your dog to lick their lips repeatedly. Seizures can also activate lip muscles and cause the smacking behavior.

Seizures can become a problem if it occurs more than once a month, or if the duration of the seizure is prolonged. Veterinary attention is highly recommended, as anticonvulsant medications can be provided to control the seizure.

Oro-Dental Problems

Oro-Dental Problems

Finally, if your dog is smacking their lips, it might indicate a painful issue involving the mouth or teeth. A physical examination at your vet will be the most effective method in identifying the condition and providing the appropriate treatment for a quick recovery.

Some potential problems can include:

Trauma to the oral region can become infected and itchy. Your dog may want to lick their lips to relieve the itchiness from the infection.

Periodontal disease is an inflammatory disease which can develop in adult dogs and dogs without appropriate oral hygiene. Over time, it can cause infections, pain and loss of teeth. In later stages of the illness, lip licking occurs more often to relieve the irritation caused by the disease.

Canine stomatitis is the inflammation of the mucous membranes within the mouth. The exact cause is unknown. However, canine stomatitis does lead to swollen gums and sores. A dog may continuously lick to temporarily stop the irritating sensation from the sores and swollen gums.

Sialocele is the swelling of internal tissues caused by leakage of saliva from the salivary glands. This causes the accumulation of saliva in the mouth, which may then induce excessive licking to move the saliva around the mouth.

Sialocele can be identified from seeing swollen bumps underneath your dog’s tongue. Surgically draining the swollen area can resolve this issue.

Tumors and foreign objects in your dog’s mouth can cause lip licking as they attempt to remove the annoying object from their mouth. Small objects like foxtails can get stuck in between their teeth, which can be uncomfortable and lead to restless nights.


When dogs smack their lips in the middle of the night, it is usually most likely a sign of dehydration or nausea due to hunger. There are other potential causes too however.

Many of the reasons why dogs smack their lips in the middle of the night are the same ones as why they may do so during the day as well.

Other possible reasons include stomach issues, cognitive problems, reinforced behavior, as well as oro-dental conditions.

To fully understand why your dog smacks or licks their lips so much, take a video of the behavior and note down any potential stimuli. These will be useful if you consider consulting with your vet or dog behaviorist on the issue.

A quick examination and the appropriate treatment can ensure you and your dog get the rest you both need at night.

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