Cat Foaming At The Mouth – Causes and Treatment


Causes                 Diagnosis                       Treatment

Cat foaming at the mouth

At a glance


  • Nausea
  • Bitter tasting substances or medications
  • Poisoning
  • Spot-on flea treatments
  • Dental disorders
  • Seizures
  • Rabies
  • Anxiety


Thorough physical examination and medical history. Baseline blood and urine tests and additional diagnostics depending on your veterinarian’s index of suspicion.


The goal of treatment is to address the underlying cause.


Foaming at the mouth and drooling are both characterised by the presence of excess amounts of saliva, I tend to define foaming at the mouth as saliva which is frothy, compared to drooling which is watery, but sometimes both will be used interchangeably.



Just like humans, cats can become car sick, which may result in drooling/foaming at the mouth due to the feeling of nausea. Other signs of nausea may include a loss of appetite and lethargy.

There are many causes of nausea including the following:

  • Kidney disease
  • Pancreatitis
  • Certain medications
  • Car/travel sickness
  • Umbilical hernia
  • Diabetes
  • Motility disorders (abnormal movement of food in the gastrointestinal system)
  • Liver disease
  • Hyperkalemia
  • Stomach ulcer
  • Gastritis (inflammation of the stomach lining)
  • Hyperthyroidism
  • Hepatic lipidosis
  • Pregnancy (morning sickness)
  • Anxiety

Bitter tasting substances

Oral and eye medications are a common cause of this as they often have a bitter taste to them.

Eye medications such as atropine can also cause a cat to foam at the mouth as once administered into the eye the medications eventually reach the back of the throat, producing a distinctly bitter taste in the mouth. Other bitter tasting medications include Flagyl (Metronidazole) and Benadryl, an over the counter antihistamine.

If the medication has been prescribed to your cat and administered as per instructions, then there is little to worry about if foaming at the mouth is the only symptom, although it is always important to let your veterinarian know. Offer your cat a small meal or a treat after he’s had his medication to help get rid of the bitter taste. If this becomes a problem for you or your cat, you can ask your veterinarian about having the medication compounded. Compounding medication can give it a more pleasant flavour such as tuna, which is more palatable for your cat. Or the medication can be in liquid form instead of tablet form. Compounding can make it easier to administer certain medications to your cat.


There are so many potential hazards out there, and cats are particularly vulnerable. Poisons which can cause frothing of the mouth include pyrethrins, poisonous toads, plants, snail bait. Look out for other symptoms of poisoning such as confusion, ataxia (wobbly gait), vomiting, diarrhea, lethargy. If your cat displays any of these symptoms, seek veterinary attention immediately.

Spot-on flea treatments

If they are applied in an area your cat can lick, the unpleasant taste can cause excessive drooling and foaming. Always apply topical flea products to the back of the neck where your cat can’t reach.

Be aware, that cats are extremely sensitive to pyrethrin and permethrin which are used in canine topical flea products. If you suspect your cat has ingested a dog flea treatment, seek veterinary treatment immediately as this is a life-threatening situation.


Seizures (convulsions or fits) are the result of a sudden and uncontrolled burst of electrical activity within the brain. They are one of the most common neurological disorders in cats, although the prevalence is much lower than that of dogs. Seizures occur in the cerebrum, which is located in the front of the skull and is responsible for sensory and neural functions as well as behaviour.

Dental problems

Several problems can affect the mouth including a broken tooth, gum disease, and stomatitis. Common symptoms of dental problems may include loss of appetite, bad breath, and pain around the mouth.


A fatal viral infection caused by the rhabdovirus. In the late stages of this disease foaming at the mouth can occur. Rabies is a rare disease in cats as most cats in the US have been vaccinated for rabies, and thankfully it doesn’t occur in Australia or the UK.

Any time you notice your cat foaming at the mouth, look for other symptoms he may be displaying. Ask yourself, has he recently had any medication, is it possible he has got into something he shouldn’t have? If you are in any doubt whatsoever, seek veterinary attention.


Find and address the underlying cause of anxiety such as inter-cat aggression or separation anxiety. In some cases, the veterinarian will prescribe anti-anti medications.

When to see a veterinarian

If your cat is drooling after administration of prescribed medication, call the veterinarian for advice,  the chances are that it is just in response to the bitter taste and aside from it being unpleasant, and your cat possibly not getting the full dose, he will be okay.

It can be helpful to take the medication to a compounding pharmacy who can flavour it to make it more palatable to the cat.

Apart from bitter tasting prescribed cat medications, seek urgent veterinary attention if your cat is foaming at the mouth. If your cat has ingested any medication, flea treatment or poison bring along the packaging for the veterinarian to look at.


Your veterinarian will perform a complete physical examination of your cat and obtain a medical history from you. He will need to ask some questions such as any recent medication your cat has been given, has he possibly consumed something he shouldn’t have as well as any underlying medical conditions your cat has and other symptoms you have noticed.

Biochemical profile, complete blood count, and urinalysis which will give your veterinarian an overall picture of your cat’s health including how the organs are functioning.

Depending on his index of suspicion he may need to perform additional tests to determine the cause. This may include diagnostic imaging of the internal organs, as well as specific blood tests.


Nausea – A symptom and not a disease itself, so determining the cause and treating is necessary. Anti-nausea medications can relieve symptoms.

Bitter tasting medications – A compounding pharmacy can compound medications to make them more palatable.

PoisoningGastric decontamination if the toxin was induced within the past two hours, this may include inducing vomiting or pumping the stomach. Activated charcoal can bind to any toxin remaining in the gastrointestinal tract. In addition, your cat will receive supportive care such as IV fluids to correct electrolyte imbalances and treat dehydration.

Topical flea products – Usually cats foam at the mouth if they ingest a small number of topical flea products. This should resolve quickly. Give your cat some water or food to help remove the taste.

Apply topical flea products to the back of the neck where your cat can’t reach. Never use topical products for dogs on your cat as these are extremely toxic.

Dog flea treatment ingestion – If you have applied a dog product onto your cat, or recently treated your dog and your cat has possibly ingested some of the product, contact your veterinarian immediately.

Treatment will depend on the severity of signs; control seizures and tremors as well as provide supportive care.

There is no antidote for pyrethrin/pyrethroid toxicity; the goal of treatment is to manage symptoms.

  • Diazepam (valium) and Methocarbamol to control seizures or tremors.
  • Gas anaesthesia may be necessary for refractory seizures (seizures which do not respond to seizure medication).
  • Intravenous fluids to maintain hydration.

Seizures – The veterinarian will need to determine and address the underlying cause as well as administer medications to help control the seizures.

Dental problems – Treatment is on a case by case basis. Some cats will only require a clean and scale. Sometimes the affected tooth is so severely damaged that removal will be necessary under general anesthesia.

Rabies – There is no effective treatment for rabies in cats and euthanasia is necessary. Due to the serious nature of the disease and the risks of transmission to humans, if rabies is suspected submission of the head to the proper authorities is required for rabies testing.


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