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dog smacking its lips

Why Do Dogs Smack Their Lips at Night? The Possible Reasons.

A dog smacking their lips at night can be troubling for a number of reasons. We look at the various causes for the behavior.

Hearing your dog smacking their lips at night can be both concerning and irritating. Of course you want your dog to be okay, but if they continue this behavior—especially without an apparent cause—it can feel like your dog is intentionally trying to bother you.

Thankfully, dogs do not intend to make their owners annoyed. Although dogs tend to develop behavioral patterns because they provide a desired result, your dog is not trying to bug you. What is more likely is that your dog is licking or smacking their lips at night because they have some sort of need.

Read on to discover some reasons why your dog may be smacking or licking their lips at night. Do keep in mind, though, that if the phenomenon is truly unexplainable or if there is evidence that it is caused by a serious problem, you should take your dog to a veterinarian for a health check. 

Hunger or Food Anticipation

One of the simpler reasons why your dog might be licking or smacking its lips at night is that it is hungry. If your dog eats one meal a day—especially if the feeding is earlier in the day—your dog may simply be wishing for more food. If this is the case, you may find that feeding your dog multiple smaller meals throughout the day curbs the unwanted behavior.

Your dog might also be licking their lips because they smell food cooking. Dogs have an incredibly powerful sense of smell (even for scents they hate). So even though you may not be making anything at home, maybe your neighbors are cooking something your dog finds enticing. Your dog may even be dreaming about smelling or eating their favorite foods, which in turn may cause the physical response of excessive licking or lip smacking.  

If your dog is licking their lips at night, it may also be a good idea to make sure they haven’t gotten into some food or found some tasty crumbs on the floor. 


Lip smacking in dogs may be a response to nausea or a precursor to vomiting. One reason dogs lick or smack their lips is to control drool, and when they feel nauseous, have an upset stomach, or are about to vomit, they may experience more saliva than usual. If vomiting is the reason and your dog does end up upchucking, the smacking or lip licking will likely stop. 

When this vomiting is a regular occurrence—especially at night—it may be an indicator of bilious vomiting syndrome. This syndrome, also called “bile reflux,” typically occurs in dogs who are only fed once a day; this causes bile to go into the dog’s stomach, where it can lead to irritation and cause vomiting. If you believe your dog is experiencing bile reflux, it is good to have them checked out by a vet, who may recommend changing the dog’s feeding schedule to include more meals. 

Acid Reflux

Like humans, dogs can also experience acid reflux. Gastroesophageal reflux, also known as acid reflux, is akin to bile reflux in that it involves digestive fluids going where they aren’t supposed to go: In this case, intestinal and stomach acid go into the esophagus and cause discomfort.

When a dog is suffering from acid reflux, they may lick or smack their lips more often due to nausea or discomfort; additionally, they may regurgitate food, belch or gag, experience weight loss, or have less of an appetite. Because this type of reflux tends to occur after eating, a dog affected by it who eats very late may show symptoms during the night. If your dog is experiencing this, they should see the vet, who may put the dog on a special diet or provide medication.

dog smacking its lips

Salivary Issues or Dry Mouth

Because lip smacking can help dogs to clear saliva from their mouths, it may be worth checking whether or not your dog is experiencing a problem with their salivary glands if they are excessively smacking or licking their lips at night. 

While some diets may cause an increase in salivation, excessive salivation that leads to lip smacking may also be caused by problems with the dog’s salivary glands. Conversely, another reason why a dog may smack their lips is due to a lack of enough saliva: an issue like dry mouth or dehydration may be the culprit in this case. In both scenarios, a trip to the vet may be necessary to solve the problem.

Dental Problems

Dogs may show that they are experiencing dental pain or discomfort by smacking or licking their lips. When dental problems like tooth or gum pain are bothering a dog, they may also show signs like pawing at their faces and mouths and discomfort when eating food.

A dog with an oral problem or dental disease will likely be bothered throughout the entire day and at night, but the extra licking or lip smacking may become more audible or obvious during the otherwise silent nighttime. 

Object or Hair Stuck in Mouth

One common reason why a dog might smack their lips at night is to dislodge something that is stuck in their mouth or in stuck between their teeth. If a foreign object is the culprit, it might be possible for you to help your dog remove it, or, at the very least, be able to identify the problem.

Things like pieces of sticks or kibble stuck between a dog’s teeth can be very uncomfortable; just like a person might try different mouth motions to remove a stuck popcorn kernel, your dog might just be trying to remove the annoyance. If your dog will allow you, you can check their mouth to see if you can help the process; however, if it is lodged in the roof of their mouth or is immovable, you should have your dog checked by a vet.  

Additionally, dogs with long hair may be more prone to making lip smacking sounds at night if they have a lot of hair around their mouths and groom before bedtime. The hair may get stuck in their mouths, then they may lick more or making smacking sounds to try to get the hair out again. The best thing to do if this is happening to your dog is to try to keep the hair around the mouth a manageable length so it doesn’t get stuck. 

dog smacks its lips at night

Liver Or Kidney Disease

Some metabolic disorders that affect the liver and kidneys can lead to excess salivation, which in turn can lead to lip smacking to control the saliva. If your dog has kidney or liver problems, this side effect may unfortunately just be one way your dog is trying to cope with the pain or symptoms, and it might be a good idea to either put them in another room when they engage in that behavior or use earplugs if you can.

Nervous System Problems or Toxin Ingestion

Dogs with nervous system problems such as seizures may smack their lips. In the case of seizures, a period of lip smacking or other abnormal behavior may occur before the seizure itself or may be part of the seizure. Because seizures most often take place when a dog is at rest or sleeping, it would not be unusual for this to take place at night or in the early morning hours. 

Additionally, certain toxins can cause dogs to drool more or lick and smack their lips. The ingestion of certain toxins may also lead to foaming at the mouth or vomiting, both of which may include lip smacking. If your dog starts to smack their lips alarmingly after a trip outside at night, it might be a good idea to make sure they didn’t get into anything outdoors. 

To Soothe Emotional Distress or Anxiety

Dogs may smack or lick their lips as a way to soothe anxiety. This type of behavior may also be associated with anxiety, though it is likely more of a coping mechanism than simply a sign that the dog is experiencing anxiety. It is a good idea, though, to try to give an anxious dog some space or remove it from whatever is causing anxiety.

Habitual Behavior

Though lip smacking and licking may indicate that a dog is trying to soothe feelings of anxiousness, the action may also just be a habit. For instance, some dogs may regularly lick their lips when settling down to go to sleep and are feeling comfortable; it is not unfeasible, then, that dogs may also smack their lips during other times when they are feeling cozy or tired.

dog smacking its lips

Lip smacking may also be an unintentionally reinforced habit tied to the owner’s reactions: If your dog regularly licks their lips at night then gets some sort of attention from you, they may associate the lip licking with getting what they want and may continue the action when they are feeling needy. In this scenario, it is best to try to ignore the dog and not respond to its lip smacking at all—eventually, it will stop associating that action with the desired result. 

Dogs may also smack their lips as a compulsive behavior, though if it is a compulsive behavior, it is likely that it will continue in the daytime, too. If you are unsure whether the behavior is compulsive or meant to provoke a reaction, you could record your dog when you are not there (or the potential trigger isn’t there) to see if they continue the action. 


Another reason why a dog—especially an older dog—might regularly smack their lips at night is because they are confused due to canine dementia, known as canine cognitive disorder. This may also be an expression of anxiety related to the condition. 

While there are certain steps an owner can take to provide additional mental stimulation to increase their dog’s mental wellbeing, canine cognitive disorder is irreversible. However, a vet would be able to assess the severity of the condition and provide advice on how best to manage the symptoms. 


Finally, a dog may smack their lips at night simply because they are dreaming. As previously mentioned, this may be because they are dreaming of eating a big steak or some other yummy meal, but it is also possible that it is just an involuntary reaction the dog is having while sleeping. In either of these cases, though it may be a little annoying, it isn’t anything to worry about.


Though it can be a bit obnoxious, lip smacking is fairly normal for dogs and is not intended to annoy. While some causes of nightly mouth smacking and lip licking are clear and fixable, others might be indicators of greater health problems.

If your dog is smacking their lips without a reason, it is probably worthwhile to have their vet check them out to make sure it is not due to an underlying health problem.

Chelsea Dickan

Chelsea Dickan

Chelsea Dickan is a long-time advocate for animals, especially those that bark or meow. When she isn't writing, she enjoys reading and watching scary movies in which the dog doesn't die.