Cats smack their lips for a range of reasons, while some are normal behaviours others are the result of medical conditions.
The most likely reason is simply that the cat has recently eaten and is tasting food remnants.
Other reasons may include excessive salivation, mouth ulcers or dental issues, dryness in the mouth, nausea, and stress.
Below are 10 of the common reasons cats smack their lips and discuss when the behaviour may be cause for concern:
1. Tasting Food Remnants
The most likely reason your cat is smacking their lips is that they are grooming themselves after eating and tasting food remnants.
This is normal behaviour and lip smacking might be a part of your cat’s daily grooming ritual.
It is common for cats to groom themselves soon after eating as they want to remove all signs of food from their lips and fur.
While grooming, they will come across remnants of the food they have just eaten and this will cause them to smack their lips.
Watch your cat closely to determine when they smack their lips and if it is exclusively after eating. If it is, there is nothing to worry about.
2. Strange Tastes
If your cat has licked something that tastes unpleasant they may begin to salivate more and smack their lips.
Things like dirt, soap, mold, cleaning chemicals etc. can cause this reaction.
The lip smacking may also be in response to taking medicine.
Increased salivation could be a side effect of the medicine or the medicine could have a bitter taste that has caused the increase in salivation.
If a strange taste is the cause, watch your cat and monitor their symptoms to make sure they are not having a toxic reaction to whatever it is they have licked.
3. Dry Mouth
Your cat may have a dry mouth or throat (also called Xerostomia).
Dry mouth is often caused by hairballs but other health issues include dehydration, fever, or kidney disease.
If a cat has a dry mouth their gums will be dry too so if you want to know if this is the cause you can check inside their mouth and look at the condition of their gums.
If your cat has a dry mouth they may be pushing their tongue out while smacking or licking their lips.
Xerostomia is more common in older cats that have previously experienced renal failure.
If you are not sure why your cat has Xerostomia and you notice other symptoms such as bad breath, high temperature, being unable to vomit but trying to, dullness in their coat etc take them to a vet for a health check.
4. Mouth Ulcers
Mouth ulcers can be painful and can cause an increase in lip-licking as well as excessive swallowing and/ or drooling.
Mouth ulcers often develop from dental diseases, oral infections, systemic infections, or ingestion of caustic substances such as dishwasher detergent.
5. Oral Infections
Oral infections cause inflammation of the mouth and tongue which will make your cat smack their lips more often than usual.
They may have something stuck in their mouth or be experiencing dental issues such as gingivitis, tartar and plaque, an abscessed tooth, or a broken tooth.
If something in their mouth is uncomfortable or irritating, your cat may be smacking their lips more than usual.
If you notice changes in your cat’s mouth, take them to the vet for diagnosis and treatment.
6. They May Feel Nauseous
Nausea generally causes hyper-salivation and a cat may lick or smack their lips as a way of getting rid of this excess saliva.
If a cat is nauseous or dehydrated they may lip-smack and then drool or vomit.
Potential causes of nausea include stress, poisoning, gastrointestinal diseases, hairballs, infections, and medicine.
7. Ptyalism (AKA Hyper-Salivation)
Ptyalism is the production of excess saliva.
This can be caused by many things and it may also be a symptom of a larger problem.
As mentioned above, hyper-salivation can occur when your cat is stressed or anxious.
The saliva can be sticky, foamy, or very liquid.
Hyper-salivation can result in continuous lip-smacking and other symptoms include vomiting and a loss of appetite.
If you notice your cat is experiencing any of these symptoms a vet check-up is recommended to rule out other health issues.
Excessive salivation can lead to your cat feeling nauseous and nausea can be accompanied by ptyalism too.
When a cat is experiencing hyper-salivation they will smack and lip their lips as a way of removing the excess saliva.
As mentioned, hyper-salivation can occur when cats are stressed or anxious and this will lead to lip-smacking and licking to remove the excess saliva.
Stress can also cause nausea which often comes hand in hand with hyper-salivation and lip-smacking too.
If you see your cat lip-smacking after hissing it is a displacement behaviour because they feel stressed or anxious.
This can lead to being aggressive, for example, hissing or biting, or your cat may be using it as a way of trying to calm down and reduce their stress.
9. Cuts Or Wounds Around The Mouth
If your cat has wounds or cuts around the mouth they will lick more and may also smack their lips.
Cuts and scratches are more common in multi-cat households but they may also have a foreign body such as a piece of bone or plant stuck in or around their mouth as well as a bite or sting on their face which is causing the lip smacking behaviour.
A close look at their face and mouth should be enough to see any cuts or wounds that are causing the behaviour.
10. A Focal Seizure
A rare cause of lip smacking is a focal seizure.
When experiencing a focal seizure a cat will often be seen excessively or uncontrollably lip licking and biting at the mouth or at the air.
During a simple focal seizure, the cat remains conscious but may appear uncertain of their surroundings.
During a complex focal seizure, the cat loses consciousness.
As cats remain conscious during a simple focal seizure it can be mistaken for a strange behaviour.
If the behaviour is not normal for your cat it could be that they are experiencing a focal seizure.
Focal seizures can be caused by a number of conditions but the most common cause is hereditary inheritance.
Other causes include brain tumors, encephalitis, viral illness, rabies, chemical poisoning, advanced kidney failure.
If you think your cat is experiencing seizures, consult a vet immediately.
This resource can give you more information on the signs and symptoms of focal seizures in cats.
What To Do About Cat Smacking Their Lips
The first thing to do is determine the cause of the behaviour.
Watch your cat closely to see when the behaviour is occurring.
If it is only happening after meals it probably isn’t an issue but if your cat is smacking their lips at other times it could be a sign of other problems.
Watching your cat’s body language can help you determine what is going on.
The behaviour may be related to stress and anxiety so your cat may be triggered by loud noises or changes to their usual routine.
If this is the case, try to eliminate the stress triggers and make any changes gradually.
As lip smacking can be a sign of medical or dental issues, taking your cat to the vet for a check-up and examination is worthwhile.
Explain the behaviour and your vet will be able to help diagnose the underlying issue and provide an appropriate treatment plan.
Why Do Cats Smack Their Lips When Sleeping?
Cats lip smacking during sleep may be caused by a dry mouth or by dreaming.
If your cat is only smacking their lips when they are sleeping it is nothing to worry about.
Why Do Cats Smack Their Lips When Being Petted?
When cats smack their lips while being petted it may be a sign they have a skin condition and the area is itchy.
If this is the case, the cat’s body language may change when they are smacking their lips.
Cat Smacks Lips When Purring
If your cat smacks their lips when purring it usually isn’t anything to worry about.
Purring is often a happy sign and when cats are happy they may drool more than normal which cause also lead to lip smacking.
If the lip smacking happens frequently and occurs when your cat is not purring then there may be an underlying cause that needs to be investigated.
Why Do Cats Smack Their Lips After Eating?
It is common for cats to smack their lips after eating, it is usually not a problem as they are just tasting food remnants.
Cats produce more saliva when they are eating to help aid ingestion and prevent dryness, this increase in saliva production can cause them to smack their lips after the meal too.
However, cats with dental issues may smack their lips more because of the tartar on their teeth, a quick look at the condition of their teeth can help you (or the vet) determine if the cause is dental issues.
Why Does My Cat Lick His Lips When He Looks At Me?
If your cat is licking their lips when looking at you it is probably in anticipation of something such as treats or a meal (especially if it is almost meal time or you are preparing their food).
At other times, it can be a sign that your cat is feeling stressed.
Cats lip smacking from time to time is no cause for concern.
It is a behaviour most often seen after eating but it can also be an indication of health issues.
If you notice your cat is lip smacking more than usual consult a veterinarian and they will be able to advise you on the cause and what to do.