Why Do Cats Leave Their Mouth Open?

Hilarious compilation videos about cats reacting by leaving cat mouth open are fun to watch. We find them as a very humorous species. But cats do this kind of behavior due to some reason.

In most cases, it’s normal, that’s how they react to certain things. Also, there are some diseases associated with this behavior.

If your cat leaves its mouth open for a few seconds, surely, it’s a great source of entertainment for you. People can spend hours seeing cats’ day to day activities, which are fun to watch.

However, if a cat leaves its mouth wide open for a long time, then there is something wrong with the cat. What can be the reason? This is what we are going to discuss today in this article.

Why Cat’s Mouth Hangs Open

As mentioned before, it can be one of your feline’s normal activities that cause no harm to it. In most cases, this harmless behavior is due to ‘Flehmen.’

Cats open their mouths when they eat, drink, groom, and vocalize. It can also happen if the cat is annoyed by something or someone. Sometimes, they leave their mouth open when they chew or bite something.

What Is The Flehmen Reaction?

Flehmen Reaction In Cats
  • Facebook
  • Twitter
  • Pinterest

The exciting thing is, apart from cats, some other mammals show this flehmen response in their day to day activities, including tigers, leopards, horses, etc.

Whenever your cat smells something unusual or unknown, it would leave its mouth open for a prolonged sniff. Cat smells that through the mouth and sends the scent to one of its organs called Jacobson’s organ for further investigation.

Jacobson’s organ, also known as the vomeronasal organ, is located in the upper part of the cat’s jaw. A very thin and small duct takes the smell into this organ where your cat studies the sample.

After taking some intensive sniffing for a few seconds, the cat stops and opens the mouth and takes a few moments to ponder upon the smell. That’s when your cat makes funny facial expressions.

When Does The Flehmen Response Occur?

This flehmen reaction triggers due to specific pheromone chemicals that animals and plants use as a mean of invisible, silent communication.

Cats secrete these pheromones as a source of a message to tell other cats whether the cat is available for mating or not, or dominant and aggressive. The receiver cat easily understands the message by judging by the reaction.

Reasons Why Cats Leave Their Mouth Open

There are some health issues associated with such behavior of cats.

Excessive Grooming

Cats usually groom themselves for self-soothing purposes. If your feline is under immense stress, the cat will do excessive grooming, which might leave the mouth open and bring the tongue out as well.


If your cat opens mouth when stressed, try to calm it down. You shouldn’t ignore the issue in your cat. Even though you give the feline all his freedom and confidence, it can still feel stressed out. Sudden change in routine is the most common reason why healthy cats are under stress.

Also, if your stressed cat opens the mouth, this indicates an acceleration in heart rate, which can bring issues if you neglect it.

There are some ways through which you can relieve your cat’s stress –

  • Ensure a safe-place or room for the cat where no one will disturb it. When the feline is under stress, it will hide in the safe-place to calm down.
  • You can use lavender spray around the home. Even though it’s toxic for cats, the smell will help to relax.
  • Also, check if you have changed anything that has to do with the cat’s diet, litter box, and living area. A sudden change in things related to cats’ living can make them stressed out.
  • Reassure the little fellow that everything is fine, nothing to worry about.

If you try these solutions and the problem persists, consult a vet. The vet will prescribe anti-anxiety medications.

Dental Problems

Cats go through several dental problems during their life. Feline gingivitis and stomatitis are the most common ones. Detailed discussion regarding the dental issue in cats is on a separate section in this article.

High Body Temperature

It even happens to humans. During scorching summer days when the temperature is so high, it increases the thirst; thus, causes dry mouth. So, until the thirst goes away, your cat is most likely to open the mouth while leaving the tongue out.

Unusual Taste Sensation

Sometimes your cat may not enjoy the texture of the food. If the cat ate any toxic food, it could happen as well. In that case, seeking emergency veterinary attention is a must.

Reasons Why Your Cat Is Breathing with an Open Mouth

Why Do Cats Leave Their Mouth Open
  • Facebook
  • Twitter
  • Pinterest

Cats typically breathe slowly and mostly through their tiny nose. A healthy feline takes about 20 to 30 breaths per minute. The numbers vary depending on the cat’s activity. A relaxed dozing cat will breathe a bit lower in number, while an active cat will breathe faster than average.

If you notice that your feline is breathing through the mouth throughout the day without doing any intense activity, you need to keep an eye on it, as this behavior isn’t normal in cats.

There are some medical conditions associated with such breathing issues that cause cats to open their mouths most of the time.


It might sound weird if you are learning about feline diseases for the first time, but yes, your cat can have asthma issues. Around 5% of cats have asthma. It can be dangerous if left untreated.

An infected cat would struggle inexplicably to breathe, accompanied by constant coughing, and these are the significant symptoms of asthma in cats.

If you suspect anything like this, be sure to let the cat go through a formal diagnosis. There is no permanent remedy to this disease for cats. However, you can improve the condition through medication. The drugs usually are taken orally or through injection or inhaler.

Pleural Effusion

When there is an abnormal build-up of fluid within the area of chest and lungs in cats, this condition arises. The symptoms of pleural effusion include –

  • Over-hydration
  • Hernias
  • Protein deficiency
  • Internal bleeding
  • Fungal, bacterial, viral infections
  • Cancerous tumors
  • Liver, kidneys, pancreas, heart failure

To prevent the disease from impacting severely, the cat needs to be examined after every physical trauma. If you wait for symptoms, it will be too late.

The infected cat must go through immediate treatment. This includes draining the fluid from the chest using a needle.

You can reverse the disease if you start treatment during the early stage. Your feline needs to go through some lifestyle changes so that the condition doesn’t return.

Respiratory Diseases And Infections

  • Facebook
  • Twitter
  • Pinterest

Cats aren’t prone to common colds like us. Most common respiratory tract infections in cats are – 

  • Feline calicivirus
  • Feline herpes (FHV-1), also known as feline viral rhinotracheitis
  • Chlamydophila felis
  • Bordetella bronchiseptica

The treatment for this disease depends on your cat’s lifestyle. If it’s a bacterial infection that’s causing the problem, the vet will prescribe antibiotics.

Ensure a peaceful and quiet place for your cat to live in. Your feline will be able to recover if it can rest for about three weeks. As respiratory infections are highly contagious, you need to quarantine the cat during the entire period.

Heart Disease

Heart issue also causes heavy breathing in cats; if left untreated, it can cause heart failure. The symptoms of heart disease in cats are –

  • Lethargy and weakness
  • Fainting and collapsing after physical activity
  • Elevated heart rate even in relaxation states
  • Paralysis of hind legs

But if you take proper steps before it’s too late, heart disease in your cat can be controlled easily.


If you own a cat, you know how much the feline loves the sun. Sunlight easily attracts their paper-thin skin. If your cat is under the sun for prolonged hours, it might cause heatstroke. Breeds that have skinny fur and long-hair can easily get affected by overheat.

Lung Cancer

Smokers aren’t the only victim of lung cancer. Cats also develop lung cancer due to many reasons. An affected cat will have low energy levels and poor appetite. Frequent fever can also occur accompanied by sudden weight loss. Some cats even cough up blood due to this disease.

Lung cancer causes cats to open their mouths and breathe rapidly.

Why Cats Leave Their Mouth Open and Don’t Eat or Groom

Felines are prone to dental issues. Almost all the cats are most likely to experience some dental issues at some point in their life. Symptoms of having a dental problem in cats are –

  • Bad breath
  • Pawing at the mouth
  • Excessive drooling
  • Stained or discolored teeth
  • Swollen or bleeding gums

You need to brush your feline teeth with cat-specific toothbrushes and toothpaste regularly. The cat will not enjoy it; still, you have to do it to keep the teeth clean and prevent damaging.

Even if your cat’s teeth look pearly white, still you need to take good care of its dental health.

Periodontal Disease in Cats

Periodontal disease refers to teeth and gum infection of cats. There are three primary stages of periodontal disease.

1. Gingivitis

It’s an inflammation of the gums. Food debris and bacteria accumulate both teeth and gums and make plaque. If the plaque is left untreated for a long time, the layer hardens and turns into tartar. This infection, later on, causes an inflammatory reaction in gums and turns reddish.

This form of gum disease is common in cats. Young and kittens are more susceptible to gingivitis.

There are three stages of gingivitis –

Mild gingivitis is when plaque starts to build upon the teeth. If you clean up the plaque from your cat’s teeth, mild gingivitis will disappear.

Moderate gingivitis is referred to the condition when plaque turns into tartar. In most cases, it separates the teeth and gum in moderation. Feline gum can retract due to this instance.

Severe gingivitis occurs when a significant amount of plaque and tartar inflames the gums. The vet will give your cat anesthesia to reverse this gingivitis. For severe cases where the gum is inflamed way too much, your cat may go through tooth extraction.

2. Stomatitis

Stomatitis is a severe form of gingivitis that affects the entire mouth tissues of a cat. It occurs when gingivitis has an extreme reaction with the plaque resulting in intense inflammation of gums and tissues surrounding it. It also causes a bacterial infection, especially when your cat bites wild prey.  

An affected cat has red and swollen gums, bad breath, gum bleeding during the advanced stages of gingivitis and stomatitis. That’s the reason why the affected cats leave their mouth open to minimize the pain.

3. Periodontitis

It’s an advanced form of gum disease, which is commonly found in senior cats. Periodontitis causes the root of your cat’s tooth to expose. It loses the connection between tooth and gum and separates them. Tooth extraction is required, as the tooth will eventually fall.

Home Remedies for Cat Mouth Infection

  • Facebook
  • Twitter
  • Pinterest

Feline gingivitis and stomatitis are such diseases that pretty much every cat suffers from. However, with some home treatment, you can effectively reverse the infection and prevent it from further occurring.

Feline Stomatitis Natural Treatment

Natural supplements can minimize dental inflammation in cats. If your cat’s gums bleed or are inflamed, consider following these steps –

  • Apply a cotton swab of feverfew, tincture (alcohol-free) of calendula or echinacea, and gently apply to feline’s gums. Do the same two to three times a day.
  • A grapefruit seed extract has potent anti-bacterial, fungal, inflammatory properties. Mix the seed extract with one tsp of coconut oil or one tsp of water, and apply to the gums using a cotton swab three times a day.

You can try these treatments for gingivitis disease as well.

Feline Stomatitis Diet

A healthy diet can also help improve inflammatory dental problems in the feline. An anti-inflammatory diet will eliminate carbohydrates and starches that are biologically unnecessary for cats.

  • Give your feline some of your own food, such as seedless apples, carrots, celery; these foods remove bacteria and clean the teeth.
  • If your cat likes fruit, try a spoonful of melons, citrus, and berries.
  • Feeding your feline sprinkling Ceylon cinnamon with its regular diet will help dissolve food particles. A tsp of fresh mint, spearmint, peppermint, cilantro fight against bacterial growth.

Improving Bad Breath In Cats

Cat gingivitis makes your cat’s breath smell really bad. You can wash the odor away using simple home remedies.

  • Mix two tsp of warm water with 1/8 tsp of Ceylon cinnamon and squirt into your furball’s mouth using an eyedropper. It will freshen the breath.
  • Mix echinacea and goldenseal with water and then microwave the mixture. Let it cool for an hour straight and shot into your cat’s mouth using a dropper.

Brushing Up

Regularly brushing up the teeth of your cat is the best way to prevent dental problems from occurring. Cats are prone to periodontitis because they don’t brush like us, and plaque build-up after they consume food.

It takes time to get your cat used to brushing. So, at the very beginning, gently massage your cat’s gums using a cotton swab or your fingers. When you find the cat is used to this habit, introduce feline toothbrush and toothpaste.

Why Recently Adopted Kitten Opens Its Mouth

Have you recently adopted a kitten, and it bites and nibbles your hand? It’s most likely that the kitten recognizes you as a threat and waits for an opportunity to strike, which keeps the mouth open. The good thing is, there is no health issue associated with this habit of your kitten.

To change such behavior, you need to coach the kitten to not consider your hands as a toy. When the cat bites your hand, remove the hand from its presence. If you are playing with the kitten and it bites so hard, stop playing and walk away.

No matter how many times you say don’t do so, the furball will not get it. So, try to push in its brain that if you bite, that would be a temporary end to fun and playtime. Engage in some hunting games with the kitten using toys. It will help to recognize the toys as preys and eventually will make it forget about your hands.

Final Words

Just because your cat leaves its mouth open for a few moments, that doesn’t mean you have to visit the vet. Observe the feline for a couple of days. If you see the furball is continuously doing this for an unusually long time, consult with the vet.

1 thought on “Why Do Cats Leave Their Mouth Open?”

Leave a Comment

Pin It on Pinterest