Why Does My Cat Drool So Much When Purring?

Why Is My Purring Cat Drooling So Much?

If your cat is purring up a storm but also leaving wet spots all over your furniture and clothes, you’ve likely wondered why this strange behavior happens. Excessive drooling isn’t normal for felines, so what gives? In this article, we’ll explore the reasons for purr-triggered drool and when it may indicate an underlying medical issue needing veterinary attention.

Normal Cat Salivation

Cats typically produce saliva at a rate of around 5-10 ml per kilogram of body weight per day, according to veterinary studies. This saliva is produced by salivary glands and acts as a lubricant to aid in chewing and swallowing food. The saliva contains enzymes that help start to break down starches and fats in the food during chewing.

It’s normal for cats to drool a little bit when excited or happy, such as when being petted or when anticipating a treat. Some drooling can also occur during sleep. Excessive drooling is defined as drooling that soaks the fur under the mouth. This level of drooling is not normal and can indicate an underlying health issue.

Cats generally keep their mouths closed and swallow frequently, so heavy drooling is unusual. Light drooling may happen occasionally, but consistent heavy drooling or drooling accompanied by other symptoms should be evaluated by a veterinarian.

Purring and Drooling

The purring reflex in cats comes from involuntary twitching of their laryngeal and diaphragmatic muscles as they inhale and exhale 1. This twitching produces a vibration or low-frequency rumbling sound. Purring occurs during times of contentment but can also happen when a cat is injured or ill as a soothing mechanism 2.

While purring is normal, it can sometimes trigger excessive drooling in cats. The vibration from purring along with increased saliva production can cause drool to drip out of a cat’s mouth. Cats may also drool from the neurotransmitter dopamine being released when purring contentedly. Excessive dopamine can stimulate salivation. So purring itself does not directly make cats drool more, but the relaxation and dopamine release that accompanies purring can lead to increased drool production.

Stress and Drooling

Stress and fear are common causes for increased drooling in cats. When cats experience stress or anxiety, their bodies release hormones like adrenaline that can stimulate saliva production. This is an instinctual response stemming from their days as predators in the wild – increased salivation helped lubricate their mouths to aid in taking down prey during tense hunting situations.

Common stressors that may cause a cat to drool temporarily include:

  • Car rides
  • Vet visits
  • Loud noises like fireworks or thunderstorms
  • Introduction of a new pet or person
  • Conflict with another pet in the home
  • Change in routine or environment

Excessive drooling paired with lethargy or other signs of anxiety indicates a cat is very distressed and steps should be taken to identify and remove the stressor. Temporary stress-related drooling is normal but persistent drooling could signal an underlying health issue.

Nausea and Drooling

Nausea is a common cause of excessive drooling in cats. When cats feel nauseated, they tend to salivate and drool more. This is because nausea stimulates the salivary glands and promotes the production of excess saliva. According to the Feline Medical Clinic 1, nausea is associated with several underlying conditions in cats including:

  • Liver disease
  • Kidney disease
  • Gastrointestinal inflammation
  • Cancer
  • Toxins or poisons
  • Medication side effects
  • Motion sickness

For example, gastrointestinal foreign body obstructions, like hairballs or eaten string, can cause nausea and drooling as per PetMD 2. Any condition that causes nausea triggers the salivary glands and makes cats drool excessively even when purring or sleeping.

Oral Health Issues

One of the most common oral health problems in cats that can cause excessive drooling is a condition called stomatitis. Stomatitis is an inflammation and ulceration of the tissues in a cat’s mouth, including the gums, tongue, lips, and palate (Source). Stomatitis is extremely painful for cats and causes severe discomfort when eating or drinking.

The main symptoms of stomatitis are excessive drooling and difficulty eating and swallowing. Cats may paw at their face or mouth due to the pain. You may also notice bad breath and red, swollen, or bleeding gums (Source). In severe cases cats may become lethargic and lose weight due to their inability to eat properly.

Treatment focuses on managing pain and inflammation. Antibiotics, anti-inflammatory medications, and immunosuppressants may be prescribed. In extreme cases, full mouth tooth extractions are sometimes necessary to remove the source of the irritation and allow healing. Maintaining good oral hygiene through brushing and professional cleanings can also help reduce flare-ups.

Toxins and Drooling

Toxin exposure is one possible cause of excessive drooling in cats. Ingestion or contact with toxic substances like antifreeze, rat poison, or household cleaners can lead to irritation and inflammation in a cat’s mouth, resulting in increased saliva production and drooling.

According to Pet Health Network, common household toxins that may cause a cat to drool include insoluble calcium oxalate plants like dieffenbachia, philodendron, and pothos. While rarely deadly, ingestion of even small amounts can result in severe drooling as the mouth tries to flush out the irritant.

Other concerning toxins include antifreeze, which has a sweet taste that appeals to cats but can cause kidney failure, and rat poison containing warfarin or bromadiolone. According to Bettervet, exposure to these kinds of toxins leads to more severe drooling as they can seriously harm a cat’s health.

Other Medical Causes

There are several other medical conditions that can cause a cat to drool excessively:

Kidney Disease: Kidney disease is common in older cats and can lead to nausea, oral ulcers, and bad breath which causes drooling. Treatment involves IV fluids, medication, dietary changes, and addressing any underlying causes (Source).

Diabetes: Uncontrolled diabetes causes excessive thirst and increased saliva production. It’s treated through insulin, diet, and weight control if needed (Source).

Hyperthyroidism: An overactive thyroid gland increases metabolism leading to drooling. Medication, radioactive iodine therapy, or surgery can treat it (Source).

Poisoning: Exposure to toxins like antifreeze, pesticides, or certain plants can cause drooling. Treatment involves removing the toxin and supportive care (Source).

Pay attention for other symptoms like lethargy, vomiting, weight loss, increased thirst or urination. Seek prompt veterinary care if your cat has excessive unexplained drooling.

When to See the Vet

In most cases, occasional cat drooling is normal. However, excessive drooling or drooling combined with other symptoms warrants a veterinary visit. According to veterinarians, you should have your cat examined if they exhibit any of the following:

These signs may indicate an oral health problem like stomatitis, nausea, oral tumors, or a toxin ingestion requiring veterinary attention. It’s important not to ignore excessive drooling, as it could signify a serious medical issue. Contact your vet promptly if your cat’s drooling seems abnormal.


In summary, while some drooling is normal for cats when they are purring, excess drooling can be a sign of stress, nausea, oral health issues, toxins, or other medical problems. Drooling when purring is likely not a cause for concern if your cat seems otherwise healthy and happy. However, if the drooling is excessive or accompanied by other symptoms, it’s important to see your veterinarian. They can examine your cat and determine if an underlying condition is causing the increased drooling.

If your cat has started drooling excessively or uncharacteristically when purring, monitor them closely and document any other symptoms. Don’t hesitate to call your vet, as prompt treatment can help manage many conditions leading to increased drooling. With your vet’s help, you can get to the bottom of your cat’s drooling issue and restore their health and happiness.

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