Cat Foaming At The Mouth: A Veterinarian Shares What to Do

At a glance

Foaming at the mouth causes:

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

Diagnosis: Cats will require a thorough physical examination and medical history. Baseline blood and urine tests and additional diagnostics will likely be needed to evaluate your cat’s health.


There are many things that may cause a cat to drool or foam at the mouth. By far, the most common reason for this is nausea, which could be due to illness or motion sickness.



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.

Common causes of nausea include:

  • Kidney disease
  • Pancreatitis
  • Certain medications
  • Car/travel sickness
  • Motility disorders (an abnormal movement of food through the gastrointestinal system)
  • Liver disease
  • Hyperkalemia (high blood potassium)
  • Stomach ulcers
  • Gastritis (inflammation of the stomach lining)
  • Hyperthyroidism
  • Hepatic lipidosis
  • 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. 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 per your veterinarian’s instructions, then there is little to worry about if foaming at the mouth is the only symptom. However, it is always important to let your veterinarian know of the issue. Offer your cat a small meal or a treat after they have had his medication to help get rid of the bitter taste.

If the administration of a bitter-tasting medication 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 palatable flavor, which your cat is more likely to enjoy.


There are so many potential hazards out there, and cats are particularly vulnerable. Poisons that can cause frothing of the mouth include pyrethrins, poisonous toads, plants, snail bait, and many others. Watch for additional symptoms of poisoning including confusion, ataxia (wobbly gait), vomiting, diarrhea, and lethargy, and seek immediate veterinary attention if you suspect your cat has consumed a toxin. 

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 dog topical flea and tick products. If you suspect your cat has either ingested or been exposed topically to a dog flea or tick 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 behavior. Signs of seizures that may be witnessed range from a small tremor or twitching of the muscles to severe paddling of the limbs and loss of control of the bowel and bladder.

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.


When cats are anxious they may hyper-salivate. This may occur when they are traveling in a car or upon trips to their veterinarian. If your cat is plagued by anxiety, speak to your veterinarian about strategies to help.

The Bottom Line

Any time you notice your cat foaming at the mouth, look for other symptoms they may be displaying.  If there is not a clear-cut reason, such as anxiety after a car ride or a foul-tasting medication, it is always safest to consult your veterinarian.


When to see a veterinarian

If your cat is drooling after the administration of prescribed medication, call the veterinarian for advice. It is likely that it is in response to the bitter taste of the medication. Aside from it being unpleasant, and your cat possibly not getting the full dose, the episode will pass and they will be okay.

It can be helpful to take the medication to a compounding pharmacy who can flavor 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 toxin, bring along the packaging for the veterinarian to look at.


The veterinarian will perform a complete physical examination of your cat and obtain a medical history from you. You will be asked if the cat has consumed something they shouldn’t have and if there are any underlying medical conditions. 

Biochemical profile, complete blood count, and urinalysis will give your veterinarian an overall picture of your cat’s health including how the organs are functioning. Additional diagnostics may be needed depending on the situation.

Treatment Options

Nausea – This is a clinical sign and not a disease itself, so determining the cause and treating it is necessary. Anti-nausea medications can relieve symptoms.

Bitter tasting medications – Offer the cat a small amount of food or water immediately after administering medication or consider using a compounding pharmacy to make it more palatable to the cat.

Poisoning – The treatment will vary greatly depending on the toxin ingested and how long it has been since ingestion.  Gastric decontamination may be appropriate for some toxins that were ingested no more than an hour ago. Activated charcoal may be used to 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 – Foaming at the mouth due to appropriate cat topical flea products should resolve quickly. You should ensure to place the product out of the reach of your cat’s mouth. There are many OTC products marketed to cats that can cause toxicity however so if drooling or foam is seen after application, always contact your veterinarian.

Dog flea treatment ingestion – If you have accidentally applied a dog product onto your cat, or recently treated your dog and your cat may have been exposed, contact your veterinarian immediately as this is a medical emergency.

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 for dental issues in cats will depend on the underlying cause. Stomatitis is often managed with diet change and medications. Diseased teeth will need a complete dental prophylaxis under general anesthesia with dental x-rays to evaluate the teeth. It is common to have to extract diseased teeth.

Rabies – There is no effective treatment for rabies in cats and euthanasia is necessary. Veterinarians are required by law to report any animal with rabies to regularity authorities.


Cat foaming at the mouth with blood

If you see your cat drooling or foaming at the mouth and there is blood in the saliva, you will understandably be concerned. However, the presence of blood is typically due to a dental issue such as an infected tooth or stomatitis. Alternatively, the cat may have an injury to its mouth which is bleeding. Regardless, if blood is seen you need to take your cat to your veterinarian as soon as possible.


Frequently Asked Questions:

What household items are poisonous to cats?

Unfortunately, there are many common household items that are toxic to cats. Some common examples include:


How long does it take to notice rabies in cats?

If a cat is bitten by a rabid animal and the virus is transmitted, the incubation period, or time from infection to the cat beginning to show clinical signs of rabies is typically 2 weeks to 2 months but can be delayed for years.


What are first aid options you can do at home? 

If your cat is foaming at the mouth or drooling, and you are certain they have not come into contact with a toxin or a rabid animal, you may offer them water and food if they are hungry. Watch the cat closely and if the issue does not resolve or the cat shows other signs of illness, contact your veterinarian immediately.


  • Dr Whittenburg, Hospital Director

    Dr. Jamie Whittenburg (DVM) is the director of Kingsgate Animal Hospital, a full service veterinary hospital in Lubbock, TX, and a medical director at Cat World. She graduated from Kansas State University College of Veterinary Medicine in 2006. Dr. Whittenburg then went on to pursue post-graduate training at Texas A&M University. She worked as an associate veterinarian in Fort Worth before the Hub City called her home. In Lubbock, Dr. Whittenburg continued her work as an associate veterinarian and in academia. On May 1st, 2013, she opened her own hospital, Kingsgate Animal Hospital, in her hometown of Lubbock, TX. She has a special interest in feline medicine and surgery.

  • Julia Wilson, 'Cat World' Founder

    Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio