Why is My Cat Foaming at the Mouth?

Picture of a cat

Cats can become sick for a variety of reasons, and they can express foaming at the mouth or excessive drooling. But sometimes, it can also happen because of stress, such as a visit to the veterinary clinic.

In this post, we will look at the most common causes of this mishap, and we’ll also tell you when it’s time to go to the vet.

Fear or stress

Most cats drool or foam at the mouth when they are put in potentially anxiety or fear-inducing situations. Some will also shake visibly or begin to purr in an attempt to calm themselves down. That is why, if your cat gets very scared when going to the vet, the veterinarian might even have a hard time examining her.

A potentially toxic ingestion

Cats are far more sensitive compared to other animals, so they can develop drooling and foaming at the mouth as a result of being exposed to certain substances. Using pet-friendly cleaning solutions is a good idea even though you might think that your cat isn’t going to get sick — after all, she’s not going to lick the floor, right?

But cats groom themselves, so sometimes they can be exposed to dangerous levels of toxic substances without you even telling that they are.


Since nausea is a symptom, it is caused by an imbalance or a disease. If a cat wants to vomit, whether she manages to or not, she will most likely drool or foam at the mouth due to nausea. Nausea can be caused by a variety of medical conditions, but also by motion sickness.

Some of the most common causes of this symptom are pancreatitis, anxiety, pregnancy, stomach ulcers, gastritis, and even diabetes. Kidney disease can be another culprit, and most cats that have it will vomit a dark, almost black substance.


There are some drugs, such as Benadryl or Flagyl, that are bitter-tasting, and that can be bought without a prescription from the veterinarian. If the vet has already instructed you on how to give these medications to your cat, they might have mentioned that cats don’t really like their taste.

In some situations, they can foam at the mouth because of this, and the worst thing about it is that along with the drooling or foaming, they might also expel the pill or the liquid form of medication.

Ask the veterinary staff to have the medication compounded if your cat has this problem, as it makes things a lot easier for both of you.

Dental problems

Although actual foaming at the mouth is less common if your feline friend has developed a dental condition, excessive drooling is not. Gum disease, stomatitis, periodontitis, and even cavities or a broken tooth can all cause pain, discomfort, and along with them, drooling.

Dental disease can be dangerous as your cat ages since periodontitis, for instance, can have severe implications on your feline companion’s cardiac health.


As rare as it can be these days thanks to widespread pet vaccination plans, rabies is still a dangerous zoonosis (a disease that can be passed from animals to humans), and more importantly, one from which no one has ever recovered. Excessive drooling and foaming at the mouth are very common in the late stages of the condition, but there are other signs that a rabid cat will display.

Cats that have rabies are either very weak and disoriented or aggressive and restless, and they also vocalize very often. They can transmit the rabies virus to people if they bite them.

Make sure that you vaccinate this cat against this disease and other infectious and zoonotic ones.

When do you have to take your cat to the vet?

If your feline friend exhibits this symptom only when she is stressed, there’s not much you can do about it other than ensuring that the animal lives in a quiet and calm environment.

However, if the foaming at the mouth is associated with other symptoms, such as frequent bouts of diarrhea or vomiting, indigestion, halitosis (bad breath), changes in the cat’s stool’s consistency or frequency, seizures, or any other clinical signs, you should take your pet to the vet as soon as possible.

Since the treatment can vary a lot from one condition to the next, the vet will have to perform a number of tests to determine just what has caused your cat’s drooling or foaming at the mouth. If no apparent or clinical cause is determined, it’s quite likely that the animal is doing it because it is stressed.

There are treatment plans for treating anxiety and stress in cats, and they can cost around $150 to $200. But if your pet is diagnosed with a dental problem and she needs surgery, the cost could just as well go up to $850 or more. Try to get pet insurance if you believe that these costs would significantly affect your budget.


Since the causes of foaming at the mouth can be so varied, preventing any such episode can be a little challenging. However, you can use pet-friendly cleaners in your home and try to keep your cat away from potentially toxic substances or foods.

When you take your feline friend in for her regular annual checkup, ask the vet to look at her teeth, and see whether a teeth cleaning procedure might not be necessary. More often than not, it is required, because cats do not accept having their teeth cleaned with a brush (some dogs might accept this).

When you administer anti-flea or anti-tick medication, always make sure that you stick to the instructions provided to you by the veterinarian or at least those available on the product packet. Even topical products can be dangerous if you have several cats in your household and they tend to groom each other.

If you suspect that your kitty has eaten or ingested anything dangerous, take your pet to the vet clinic right away — time is of the essence in intoxications, whether in people or animals.

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Cristina Vulpe PhD

Cristina Vulpe PhD

With a PhD in Veterinary Oncology, Dr. Cristina Vulpe loves researching and writing about the things that she’s passionate about. These range from animal nutrition and welfare to pet behavior, infectious diseases, and parasitology. In her spare time, she’s always in the company of her cat and a good book.

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