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17 Alarming Reasons Why Dogs Smack Their Lips At Night

Dog Smacking Lips In Middle Of Night

If some people’s nights are quiet and peaceful…

Yours are the exact opposite.

Your pooch always makes these smacking sounds in their sleep.

Like they’re licking an invisible popsicle or peanut butter.

This often keeps you and your dog awake the whole night. 

So now you’re probably wondering…

“Why are they doing this?

And should I be worried?”

Continue reading to find out:

  • 17 alarming reasons dogs smack their lips at night.
  • Why canines usually do this during those late hours.
  • Several possible dangers if your dog does this frequently.
  • Helpful tips on how to help dogs with this kind of behavior.
  • And much much more…

Why do dogs smack their lips in the middle of the night?

Dogs smack their lips in the middle of the night due to nausea or anxiety. Dry mouth and dental issues are also likely. As well as seizures, OCD, or dementia. Some dogs may also do this when they’re hungry or done eating something. While other canines do it before bed or even while they’re dreaming.

17 reasons why dogs smack their lips at night

#1: Bilious vomiting syndrome

If your dog only smacks their lips at night and they also vomit some greenish-yellow liquid…

They might have bilious vomiting syndrome, a.k.a. ‘bile reflux.’

“What is it?”

Before we talk about the condition, let me explain what bile is first.

It’s a greenish-yellow ‘juice’ that’s created by the liver. And it’s stored in the gallbladder as we eat.

Then when it’s time for digestion, the bile enters the small intestine. Which helps in breaking down food – especially fats.

Now, for some unknown reasons, it can also go into the stomach. And this causes irritation.

“What are its symptoms?”

According to PetMD, canines who have this will often feel nauseous at night. Hence, the constant lip-smacking.

This may also occur in the morning. Along with other symptoms such as stomach pain and reduced appetite.

Vets say that the exact cause for this illness is still unclear. 

However, it might be a result of having an empty stomach for so long. Since it usually affects canines who are fed only once a day.

Note: This can be treated by medications. But if it still persists, vets may advise some diet changes. Like switching to food low in fiber and fats. And also, offering dogs small but frequent meals at night.  

#2: Nausea

Your Dog Smacks His Lips In The Middle Of The Night When He Has Nausea

Does your dog also drool a lot while they smack their lips?

And do they also lick any surface they see?

If so, they might be nauseous.

But, this isn’t due to the build-up of bile in the stomach.

“So what may have caused this?”

Based on VCA Hospitals, nausea can be a symptom of several illnesses.

One of these is an upset stomach and it could be a result of:

  • Parasites.
  • Poisoning.
  • Pancreatitis.
  • Food allergies.
  • Changes in diet.
  • Intestinal obstruction.
  • Viral or bacterial infections.
  • Ingesting non-edible and spoiled food.

Nausea can make dogs’ tummies feel sick. And their mouths will also become watery.

Which explains the excessive lip-smacking and swallowing.

What to do?

Most cases are only mild. And they’ll usually resolve on their own within 24 hours.

However, if this still persists, consult your vet right away. Especially if they start showing these other signs:

  • Fever.
  • Stomach pain.
  • Vomit with blood.
  • Reduced appetite.

Note: Vets will also recommend withholding of food from 6 to 48 hours. Depending on their condition. Then once the vomiting stops, dogs should be offered small amounts of water and bland food. Say, plain boiled chicken bits and white rice.

You might also like: Why do dogs pretend to bury food with their nose?

#3: Acid reflux

Next, lip-smacking can also be a sign of acid reflux.

This condition occurs when the matter in the stomach goes back and forth into the esophagus. (A tube that links the throat to the stomach.)

And just like nausea, this will also cause dogs to drool and lick their lips many times.

“What are its other signs?”

Canines who have acid reflux will also become restless at night

Some Fidos may even act crazy and throw up. And they’ll also display these other symptoms:

  • Fever.
  • Bad breath.
  • Spitting of food.
  • Lack of appetite.
  • Excessive drooling.
  • Persistent coughing.
  • Unusual bark sound.
  • Difficulty in swallowing

“How do dogs get this?”

Food allergies may cause this condition.

Some of the common culprits are soy and gluten. As well as preservatives and food coloring.

But, this could also be a result of recurring vomiting. And it’s often seen in younger dogs too.

What to do?

Experts say that acid reflux can be managed at home by:

  • Withholding food for 1 or 2 days.
  • Not giving dogs food high in fats.
  • Serving food low in fat and protein.
  • Feeding them small meals in short intervals.

But for severe cases, vets may prescribe medications to lessen stomach acidity. Like Pepcid and Apo-Famotidine.

You might also wonder: Why does my dog suddenly smell like fish?

#4: Xerostomia

This is the medical term for dry mouth.

And as its name suggests, this condition is characterized by a decrease in saliva.

Due to this, dogs will experience discomfort in their mouth. Which causes them to smack their lips repeatedly.

Besides this, vets say that they’ll also have:

  • Bad breath.
  • Thick saliva.
  • Difficulty in chewing.
  • Swollen oral tissues.

This is likely caused by extreme dehydration. Which is one of the reasons why dogs drink plenty of water at night.

But, dry mouth can also be due to:

  • Fever.
  • Salivary gland diseases.
  • Immune system dysfunction.
  • Medications (e.g., antihistamines, decongestants, diuretics, sedatives).

What to do?

  • Find out its main cause first and treat it.
  • Ensure that your dog drinks enough water daily.
  • Always refill their bowl with clean water before bedtime.
  • Provide your dog food high in moisture (e.g., canned food, cucumber, watermelon).
  • If this behavior appeared after taking a certain drug, call your vet. So that he or she could lessen the dosage or give an alternative.

Warning: Dehydration might look like a simple condition. But, it could be fatal if left untreated. So if your dog is lethargic and vomits a lot, call your vet asap.

And also, encourage them to drink more water to replace the fluids they’ve lost.

If your pooch refuses to drink and you want to know more tips,

Check out this article: 27 Easy Ways To Trick Your Dog Into Drinking Water (How-To)

#5: Dental issues

Your Dog Keeps On Smacking When He Has Dental Issues

Dogs can also make those lip-smacking sounds if they feel pain inside their mouth.

And this is likely due to dental problems.

According to experts, the common dental issues in dogs are:

  • Loose tooth.
  • Gingivitis: Inflammation of the gums.
  • Tooth root abscess: Infected root canal.
  • Periodontitis: More severe gum disease.
  • Plaque: Buildup of bacteria or food debris on the teeth.

“How do I know if my dog has pain in his mouth?”

Check your Fido’s mouth and see if they have:

  • Missing teeth.
  • Inflamed gums.
  • Discoloration of a tooth.
  • Tartar (yellowish substance).
  • A swollen part under their eyes.

If they’re in discomfort, they’ll also:

  • Refuse to eat.
  • Lose interest in hard treats.
  • Keep pawing at their mouth or teeth.
  • Frequently drop their food while eating.

What to do?

If your dog shows some of these signs, bring them to a veterinary dentist.

Usually, Fidos with dental issues will also have bad breath. And it’s something you’ve never smelled before.

So it’s a clear sign that something’s wrong.

Also, specialists may recommend some doggy dental chews or toys.

But remember, these aren’t treatments. They’ll only get rid of any plaque on your dog’s teeth. 

And lastly, to prevent any further problems, make sure to brush their teeth regularly.

“How often should I do this?”

Vets say that this should be done twice per day. And brushing each side must be at least 30 seconds.

To know how, watch this short clip:

Note: Don’t use human toothpaste and toothbrush on your dog. Buy products that are specially made for dogs – like this one. And pick a doggy toothbrush suitable for your Fido’s size.

Don’t  forget to check out: Why Does My Dog Suddenly Have Bad Breath? 9 Reasons & Tips

#6:  Sialadenosis

Apart from lip-smacking, does your pooch also retch and gulp?

If they do this quite a lot in a day, it could also be that they have sialadenosis. Or the enlargement of salivary glands.

Dogs have these glands in different locations. Such as in the neck, head, and along the lining of the mouth.

And when they’re irritated, they’ll cause discomfort to dogs. Which makes them gag and swallow frequently.

Other signs to watch out for are:

  • Snorting.
  • Depression.
  • Weight loss.
  • Hypersalivation.
  • Nasal discharge.
  • Being less active.

Research says that the reason for this is still unknown. And it’s also underdiagnosed since it’s a rare condition in dogs.

Note: A study in Israel shows that phenobarbital can treat this. It’s a medication used to control seizures. As well as insomnia.

Check out also: Why is my dog drooling all of a sudden?

#7: Necrotizing sialometaplasia

This is also a rare disease in dogs. And it targets the salivary glands as well.

Based on Merck Vets, this mostly affects small breeds. Especially ages 3 to 8 years old.

Dogs with this condition will have swollen and painful salivary glands. And its signs are similar to sialadenosis

But, affected canines may also experience:

  • Shortness of breath.
  • Abnormal rapid breathing
  • Abdominal respiration (or belly breathing).

#8: Oral foreign bodies

Dogs who often smack their lips might also have something stuck in their mouth. Which could explain the drooling and licking.

Well, canines love exploring the world through their snouts. And they may also ingest things they shouldn’t.

So, they might be doing this to get rid of the foreign body inside their oral cavity.

This could be a bone, stick, or piece of string. (The list goes on.)

These can irritate the walls of their mouth.

And if your dog keeps on licking (along with pawing at their face), the thing inside might even cause trauma.

“What are its other signs?”

Due to the discomfort, dogs may also refuse to eat.

While others will develop bad breath. And this happens when the foreign body is stuck for so long.

Note: Inspect the insides of your dog’s mouth. If you see any and it’s not too deep, you can safely remove it. But if it’s not possible, leave it to your vet.

#9: Hungry

Sometimes, canines can also make those smacking noises due to hunger.

They might be simply starving at night. Or they may have smelled something yummy.

“Wait. Do dogs also drool when they want food?”

Yup! Like us, specialists say that they could also do this in response to food.

Well, canines have an incredible sense of smell. So, they can pick up the scent of a delicious steak (for example) even from afar.

But, it could also be that…

#10: They’ve just eaten something

You might think that your dog is only imagining an invisible treat.

But in reality…

They’re actually eating some goodies!

This is more likely if you only hear your pooch smack their lips once in a while. As they’re devouring some midnight snacks in the dark.

Your pooch may have found some food crumbs on the carpet. Or even on your bed.

So you might notice that they’re licking and scratching your sheets as well.

Note: It could also be that they’ve eaten some of their hair. So they smack their lips to get rid of it. This is common in dogs with long fur. As their hair can easily get inside their mouth.

#11: Physical discomfort

Lip-smacking in dogs might also be an indicator of pain.

So, pay close attention to your pooch. And gently feel the parts of their body to detect any tenderness.

This can be due to arthritis. Especially if you have a senior dog.

But injuries and bone problems are also possible. Say, hip or elbow dysplasia.

Note: If you notice that your dog’s in pain, take them to the clinic at once. They’re in discomfort and they need some relief. The agony may also cause them (and you) to stay awake at night. And affect their everyday function. 

You might also be interested in: 13 Odd Reasons Why Dogs Whine At Night + 5 Tips To Stop It

#12: Seizures

This behavior can also be a symptom of focal seizures.

These occur only in one area of the brain. So a subtle sign like lip-smacking could be a  possible symptom.

Experts say that seizures are common in dogs.

And these can happen while they’re falling asleep or waking up. Which explains why some canines do this at night.

“How do dogs get these?”

Seizures are likely inherited. PetsWebMD share that these are common in Border Collies and Australian Shepherds.

But other possible reasons are:

  • Toxins.
  • Brain trauma.
  • Brain tumors.
  • Liver disease.
  • Kidney failure.

What to do?

During an episode:

  • Remove any things that can hurt your dog.
  • Move them away from dangerous places like stairs. As they may collapse. 
  • Avoid hugging or petting them. Instead, reassure your dog by speaking softly.
  • Don’t touch their head and mouth. They could accidentally bite you as they’re not in control of their body.

Note: Seizures lasting more than 5 minutes are concerning. So take your dog to the vet asap. But for mild cases, record and time your Fido’s episodes to help with the diagnosis.

#13: Emotional distress

Did you know that lip-smacking is also a telltale sign of anxiety in dogs?

According to the University of Bristol, it’s one of the things you’ll notice on a nervous Fido.

And it’ll also come with:

  • Yawning.
  • Pinned ears.
  • Sudden panting.
  • Constant licking.
  • A stiff facial expression.

So, what may have caused this?

The common culprits are sudden loud noises. Like roaring thunder, gunshots, or bursting fireworks.

A study found that noise phobia is a common issue in pet dogs. And 15% of fearful Fidos in the experiment needed many days to recover from fireworks.

That’s how scary those booming noises are to our furry friends. So some dogs can be extremely stressed after hearing those sounds. 


Dogs might also have trouble sleeping away from their parents. Or they’re stressed due to changes in their routine.

They’ll also feel anxious if they receive less time and attention. As well as lack of exercise and socialization.

What to do?

  • Don’t over-comfort your dog by petting or giving treats.
  • Exercise them every day. Both physically and mentally.
  • Ignore nervous behaviors. Only reward them when they’re calm.
  • Lead them back to their crate. Or give them some space to settle down.
  • For more serious cases, give them vet-prescribed medications to reduce anxiety.

For further reading: What can I give my dog to sleep at night?

#14: OCD

Anxiety might also lead to an obsessive-compulsive disorder, a.k.a. OCD.

Since licking can somehow soothe their nerves, dogs may use it as a coping method.

Then as they keep smacking their lips, they’ll become ‘obsessed’ with it. So they’ll use it every time they want to calm themselves.

Now, this behavior will become repetitive.

So as a result, anxious dogs can do it at random times as well. And they’ll smack their lips without any context at all.

Note: Experts say that OCD gets worse with time. When this happens, it’ll hinder their everyday lives. So as much as possible, get your dog checked by an expert.

#15: Canine dementia

Old dogs with memory loss will also have heightened anxiety. And this usually occurs in the middle of the night.

So this nervousness can also cause them to constantly smack their lips.

This condition is called canine cognitive dysfunction, a.k.a. CCD. Or also known as dog dementia which is similar to Alzheimer’s.

“What are its other symptoms in dogs?”

According to Dr. Petryk, you’ll notice these signs in affected canines:

Note: Aging will also bring many changes to a dog’s body. They may start having poorer vision and hearing. And these can also make them more anxious. Especially when they have to travel in the dark with no aid.

Don’t miss out on: Why does my dog wake up in the middle of the night?

#16: It’s a noisy bedtime habit

In other cases, it could also be that your dog is only soothing themselves to sleep.

Lip-smacking can be a relaxing activity too. Especially if it’s done repeatedly. 

Like how some dogs lick their paws before bed.  

#17: They’re dreaming…

Lastly, AKC shares that dogs do dream.

“But what do they dream about?” you might ask.

Well, it was said that they have similar patterns to us.

So they could be recalling some memories too. As well as seeing things they love.

And in your dog’s dream, they may be eating a large piece of meat. Or licking some peanut butter.

This is why they keep on smacking their lips as if they’re actually eating.

Should I be worried if my dog smacks his lips at night?

You should be worried if your dog smacks his lips at night. Especially if they do this frequently.

There are many possible medical reasons for this. Say, nausea, bile and acid reflux, and seizures. As well as salivary gland problems.

Your dog might have also ingested something toxic. This can also upset their stomach. And affect their nervous system. 

So if your pooch shows some of the signs I mentioned above, don’t wait any longer. Bring them to your vet at once.

Note: If your dog has a clean bill of health, anxiety is also likely. So, try to reduce this as much as possible. 

If you want to know how read this article: 19 Proven Ways To Calm Your Anxious Dog (How-To Guide)