Why Is My Cat Foaming at the Mouth? Is He Sick?

It’s not just dogs that get foaming at the mouth. Cats can also become agitated and produce foam from their mouths. In some cases, the foam may be green or brown and come out in large amounts. Why is that?

Why is my cat foaming at the mouth?

When your cat starts foaming at the mouth, you may wonder what is wrong. Foaming at the mouth can be a symptom of many different diseases or medical conditions, so it is important to consult your veterinarian for an accurate diagnosis. 

Here are a few common causes of foaming at the mouth in cats:

Dental problems

Dental problems commonly cause excessive foaming at the mouth in cats. Common dental issues that can lead to foaming include tooth decay, gum disease, and periodontal (gum) infection. 

These conditions can cause your cat to experience pain and difficulty chewing, prompting them to foam at the mouth. 

Occasionally, a dental procedure such as cleaning or extraction may also cause excessive foaming.

Blockage in the cat’s throat

When your cat starts foaming at the mouth, it could be due to a blockage in their throat. The reason for this obstruction will depend on the size of the obstruction but can generally be attributed to dietary or environmental factors. 

In most cases, cats will start having trouble breathing and rapidly develop a high fever. If left untreated, this condition can lead to death.

Food allergy

If your cat is foaming at the mouth, it could be due to a food allergy. Food allergies are common in cats and can cause many symptoms, including vomiting, diarrhea, skin rashes, and even anaphylaxis (a severe allergic reaction that can lead to death). 

To diagnose a food allergy in your cat, your veterinarian will perform an elimination trial. In this trial, your cat will be switched from its current diet to a different one for several weeks and monitored for any signs of illness. 

If your cat develops any of these symptoms after being on the new diet, it likely has a food allergy.

Upper Respiratory Tract Infection (URTI)

Your cat may be foaming the mouth due to an upper respiratory tract infection (URTI). This is a common problem for cats, especially during the winter when their immune system is weakened. 

Many types of infections can cause a loose discharge from the mouth and nose, including bronchitis, laryngitis, and pneumonia. 

Your cat may also experience a sore throat or inflammation of the tongue. Sometimes, your cat may have difficulty breathing and need to be hospitalized.

Head trauma

When your cat experiences head trauma, the pressure inside their skull can increase to such an extent that fluids and saliva start to escape from their mouths. This can cause your cat to foam at the mouth and may also cause them to have difficulty breathing.

Any type of head trauma can cause a foaming mouth. This includes bumps, cuts, or bruises to the skull or face. If your cat has been suddenly struck in the head, there is a high chance that they will experience this behavior.


Seeing your cat foaming at the mouth could mean that he has had a stroke. Strokes are caused by a sudden blockage of blood flow to part of the brain. 

This can happen when an artery is blocked or a blood clot forms in one of the vessels leading to the brain. 

Symptoms of a stroke can include: weakness on one side of the body, difficulty speaking, trouble understanding what others are saying, confusion, dizziness, and seizures.

Blocked nose or ears

Blocked noses and ears can cause air to become trapped in the respiratory system, which can lead to foaming at the mouth. 

In some cases, the blockage may be caused by a foreign object (such as hair) lodged in the nose or ear. If this is the case, your veterinarian will need to remove the obstruction and treat your cat accordingly.

Enlarged tonsils or adenoids

Tonsils and adenoids are two small glands in the back of your cat’s throat. They are responsible for helping to clean their teeth, and they also produce saliva. 

If they become enlarged, it can cause problems with your cat’s breathing. This is because when the tonsils or adenoids block your cat’s airway, they must work harder to breathe. 

The foam you see coming out of their mouths is usually a sign that they struggle to get enough oxygen.


Diabetes is a serious disease that can cause your cat to foam at the mouth. Many different things can cause diabetes, but the most common type is type 2 diabetes. 

Cats with this type of diabetes often have high blood sugar levels because their body doesn’t produce enough insulin or they can’t use insulin properly. 

This can lead to excessive sugar in the blood and foaminess in the mouth. Other causes of diabetes include:

  • Being overweight.
  • Having a family history of the disease.
  • Eating foods high in sugar.


Cancer is another possible cause of foaming at the mouth in cats, and it can be difficult to diagnose because it can look like any other health problem. 

If your cat has been vomiting or having difficulty eating or drinking, it’s important to take him to the veterinarian for a comprehensive exam. 

During the exam, the veterinarian will use an x-ray to check for tumors or other problems that may be causing the vomiting or poor appetite. 

If cancer is suspected, your cat will likely need surgery to remove the tumor or chemotherapy to treat it.

Heart disease

When the heart is working properly, it pumps blood throughout the body. But if something goes wrong with the heart, it can no longer pump blood as effectively. 

This can cause fluid to build up in different body parts, including the lungs and stomach. In some cases, this fluid might form bubbles that get trapped in the cat’s mouth and nose. 

This can lead to foaming at the mouth (or other respiratory problems) because air can’t flow easily through the bubbles.

What should you do if your cat has a foaming mouth?

If your cat has a foaming mouth, you can do a few things to help.

  1. Make sure that the cat has access to clean water and fresh food. If the cat is eating a dry diet, try moistening its food with water or milk.
  2. If the foam comes from the mouth, give your cat plenty of fluids (water or milk) and put it in a cool place to calm down.
  3. If the foam doesn’t go away after a few minutes or if it’s coming from other parts of the body, take your cat to the veterinarian.

How to prevent your cats from foaming at the mouth

Foaming at the mouth is typically caused by many different things, but there are some steps that owners can take to help prevent it.

  1. Make sure your cat has access to fresh water at all times. If their water dish isn’t constantly full, give them a little bit of fresh water before you feed them, so they’re not thirsty and trying to drink foam.
  2. Provide them with plenty of snacks and treats that contain no sugar or starch, which will help to curb their appetite and maintain a healthy weight.
  3. Avoid giving them foods that can cause allergies or other problems, such as raw fish or poultry products.
  4. Keep your cat’s coat clean and free from any mats or tangles. These can obstruct airflow in their throat, leading to foaming.
  5. Make sure they have access to a litter box that is clean and free from dust or debris. This will help to reduce the amount of saliva they produce.
  6. Keep your cat’s teeth clean. If your cat has tartar buildup on their teeth (from eating hard foods or treats), this accumulation can cause them to foam at the mouth when they chew.


There are a few possible reasons why your cat might be foaming at the mouth. It could be due to a dental problem, an throat or mouth irritation, or a health issue such as a tumor. 

If you notice that your cat is foaming excessively, take her to the veterinarian for an exam and potential treatment.

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