Dog Lip Smacking, at Night in Sleep, Causes

Dog lip smacking

Does your dog ever sound like they have a big glob of peanut butter in their mouth? Dog lip smacking may occur for a number of reasons. These may be habitual, due to anxiety and nervousness, or a symptom of a serious medical problem.

Let’s explore the many reasons your dog may be smacking their lips and what you can do help them.

What is Dog lip Smacking?

Let’s break down lip smacking in canines and look at why your dog may be preforming this act. Lip smacking is basically movement of the mouth and lips that makes a noise. You may find this sound cute and adorable or annoying and frustrating. Whatever your reaction, its important to know the cause.

Causes of Dog Lip Smacking

Anticipation of Food

Just like us other mammals often salivate when they smell food. Your dog is no different. If you are cooking a beef stew for the family or opening a can of Purina dog food, your dog may visibly react.

Dogs react to smells, sounds of cooking, and thoughts about being fed. Saliva forms in their mouth during this time of anticipation. The dog will smack his lips while moving the tongue in a lateral direction to keep the saliva from leaving the mouth.

This behavior is a natural reaction and one that will stop once the dog is fed. You may also have associated a conditioned response to a stimulus in your dog. During Pavlov’s famous work on conditioning he noticed that the dogs would start salivating as soon as they saw the assistants who fed them.

If your dogs are anything like mine, they recognize the movements you make to prepare their dinner. They respond by lip smacking, barking, or jumping up and down to let you know they are ready to eat!

In addition, if you have trained your pup using treats as a reward they may salivate after completing a command in anticipation of a treat. For instance, many people use a clicker devise in training. Your dog may learn to associate the clicker with getting a treat.


Nausea can happen for a number of reasons. Your dog may have eaten to quickly, eaten something indigestible or eaten something toxic.

When your dog has an upset stomach, he often vomits to relieve pressure on the abdomen. Before the dog vomits, saliva collects in their mouth. Contents of the stomach are very acidic, and salivating is a way to protect the mouth and throat from that acid.

As the dog salivates, they also lip smack and drool. This is a natural reaction of the body. The best thing to do is get your dog outside or into the bathroom and let them vomit. After they throw up you can give them some cool water to help relieve the irritation.

If your dog appears comfortable after vomiting it was probably a one-time event. However, if they continue to vomit or act ill then you should contact the vet’s office for guidance.

Acid Reflux

Dogs can also experience acid reflux just as humans do. This can especially occur in small dogs who have a high metabolism. When the stomach is empty gastric fluids flow into that empty space. These intestinal fluids move up from the stomach into the esophagus.

This causes irritation and inflammation. When the throat and mouth feel irritated the dog produces saliva and starts lip smacking in an attempt to manage the irritation.

The sphincter is a muscle at the base of the esophagus opening to the stomach. In healthy dogs, this muscle typically remains closed and doesn’t allow stomach fluids to enter the esophagus. In some dogs, especially smaller breeds, or senior dogs, that muscle becomes relaxed.

If this occurs frequently you should visit the veterinarian. They may suggest diet changes or a medication to help reduce acid reflux.

Mouth and Dental Issues

Many dogs occasionally smack their lips. However, if your dog does this often or consistently you may have a problem. Dogs who demonstrate lip smacking may have mouth or dental problems that need to be addressed immediately.

Object Embedded in Mouth

Puppies are notorious for chewing on things which are not always appropriate. You and your dog may have been playing fetch and a piece of wood from the branch you were throwing has become lodged in their gum.

Start by looking in your dog’s mouth and making sure there are no foreign objects in the mouth. Sometimes a piece of one of their toys has broken off and lodged in the mouth.

If you can safely remove the object do so immediately. If it has penetrated in your dog’s gums or the roof of their mouth you need to call your vet to have it safely removed.

In addition to an object lodged in the dogs mouth you may need to consider an insect. Dogs often think it is great fun to snap at a bee, wasp, or other venomous insect. When they succeed in getting there quarry it may mean a sting inside there mouth.

If this happens rinse their mouth with cold water or give them some ice chips to chew on. Keep an eye out for an allergic reaction and call the vet if there is abnormal swelling or your dog has breathing trouble.

Periodontal Disease

Dogs need regular dental care. You should aim to be brushing your dog’s teeth weekly. Your veterinarian will do an oral exam at your dog’s annual check-up. In this exam they will check for excess plaque, lose or broken teeth, and gum irritation.

Veterinarians perform teeth cleanings in a similar way as your dentist. However, dogs are anesthetized in order for this to be done safely for the vet and the dog.

Dogs don’t have a way to tell you they have a broken tooth or sore gums. So they lip smack, drool, and paw at their mouth. If your dog is having these behaviors they may need a dental cleaning to resolve the lip smacking and drooling.

Canine gum disease is quite common. Unfortunately, many dog owners don’t consider their dogs dental health. Studies such as the one at Waltham Petcare Science Institute found that 43% of miniature schnauzers, a whopping 96% of toy poodles and 84% of beagles over the age of four had developed some form of periodontal disease.


This medical condition, referred to as Sialadenosis, is caused when the salivary glands become swollen and or infected. This causes the saliva to pool into the mouth. The dog will lip smack in order to move the saliva around.

Your dog’s salivary glands are located under their tongue. Open the mouth and gently lift the tongue. If you see swollen lumps, then you need to take your furry friend to the vet. This condition responds well to medication.


Xerostomia, or dry mouth, is the opposite of sialocele. This is extremely uncomfortable for the dog. Not producing enough saliva can cause lip smacking because the dog is trying to produce saliva.

This is uncommon in a healthy dog but may occur in older dogs, especially those undergoing cancer treatment. The treatments are administering extra fluids and mouthwashes.

Canine Stomatitis

Another mouth disease that causes dog lip smacking is Canine Stomatitis. This is when the mucous membranes in the mouth become inflamed. This may cause swelling in the gums and sores along the gum line especially on the inside of the lips.

This problem can develop in any breed but is common in Greyhounds, as well as Maltese, Miniature Schnauzers, and Labrador Retrievers. This is an immune system dysfunction that causes a severe gum response to plaque.

Regular dental exams by your veterinarian are especially important.

Liver and Kidney Disease

Diseases that affect the function of the kidneys or the liver are often seen in middle aged to older dogs. You may not even notice the early symptoms such as more frequent urination and drinking larger quantities of water. Renal failure is not having less urine but of the body not eliminating the waste efficiently and cleaning the blood.

As kidney disease progresses you may see nausea, vomiting and licking lips more frequently. These symptoms in an older animal are critical and you should make an appointment with your veterinarian.


Dehydration occurs when the body does not have enough fluids. Water is critical for proper function of organs, limbs and regulating body temperature.

When your best friend does not have enough fluids their body works to protect vital systems. Fluids are moved from outside areas to the organs to protect them. This causes lip smacking, panting and dry mouth.

Dehydration may occur when we are playing with our dog and just having fun. A vigorous game of frisbee on the beech or a hike in the park can make your dog (and you) feel dehydrated.

Fluids are the answer. Stop what you are doing. Give your pooch a chance to cool down. Then let them have a good drink of water.

Ingestion of Toxins

Sometimes lip smacking is a warning that your dog has ingested something that is toxic. Did you know that many house and landscaping plants can actually be toxic or poisonous to dogs?

Dieffenbachia also known as Dumb Cane causes lip smacking, drooling, and swelling of the mouth. Other common houseplants such as Aloe Vera, Cyclamen, Jade and Sage Palm are not good to have around dogs.

If your pet has a severe reaction after ingesting a plant call your vet immediately. Do not try to make your dog throw up. You can also reach out to the Animal Poison Control Center APCC 24-hour emergency poison hotline at 1-888-426-4435.

Lick Granuloma

Sometimes in addition to lick smacking your dog also obsessively licks their skin. This is known as lick granuloma. They can actually lick the hair off exposing the skin. Continued licking can cause a hot spot or irritated area on the skin.

This can lead to a bacterial or yeast infection.

There are several things that may trigger the excessive licking. Physical problems such as skin mites, pain in a joint or bone, insect bites or some type of trauma may trigger licking. It may also originate from a psychological issue such as anxiety, boredom or stress.

Observe your pet to try to find the cause of the licking. Use positive reinforcement to distract them from the behavior. If the spot gets infected, you may need to see your vet for antibiotics.

Talk with your vet about when and where the licking occurs so you can isolate the cause.


Dog lip smacking may also be a behavioral response to certain stimuli. It may be a pacifying behavior that the dog uses in reaction to a perceived threat. Possibly a larger more threatening dog or human.

Dogs that are anxious and stressed will often lip smack or open and close their mouths. Pay attention to when this behavior is happening. If you can find the trigger you can work to reduce the stress.

Does it occur during a thunderstorm or when you encounter a new dog at the park?

If your dog is a rescue, then they may have some behavioral quirks that come from that experience. Lip smacking is associated with an animal trying to calm themselves.

Use behavioral positive reinforcement to correct and encourage. Your dog may just need some comforting words from you or a big hug.

Sources and References