Dogs drool for all kinds of reasons, but if your best mate is creating huge puddles, there might be a problem

Let’s explore the wet world of excessive salivation


What is saliva?

Saliva is a watery secretion that lubricates the mouth (and the food to aid swallowing). It also contains important substances that help digest food and keep teeth and gums healthy.

Salivary glands constantly produce and secrete saliva into the oral cavity. When we eat, saliva production increases. There are four major salivary glands on each side: parotid, mandibular, sublingual and zygomatic. How much saliva is produced by these glands is controlled by the brain. There are salivary nuclei in the brain stem that stimulate the glands to produce more saliva. There are also ‘higher’ parts of the brain that can excite or inhibit the salivary nuclei. Diseases affecting the pharynx, oesophagus and stomach can also cause excessive production of saliva

It’s kind of complex, but you just need to know that there’s more to saliva production than what’s going on in the mouth.


Terms meaning excess saliva

The medical term for excessive production of saliva is ptyalism (although we often say hypersalivation to avoid words with a silent p!)

It’s also worth mentioning the term pseudoptyalism. This is where we see a lot of drool, but it’s not due to overproduction. Instead it’s due to a problem swallowing a normal amount of swallowing or an anatomical abnormality that lets saliva dribble out of the mouth.


What causes excessive saliva production?

Because of all the different things that affect saliva production, there are lots of potential causes of ptyalism (and pseudoptyalism). Some are nothing to worry about, others are very serious.

Here is a (non-exhaustive) list. It will hopefully help explain why when you ring us up and ask: ‘Why is my dog drooling a lot?’ we might not have a simple answer.

Conformational problems

  • droopy lips – lots of large breed dogs have lip conformation that allows saliva to dribble out

oral and pharynGeal problems

  • foreign body (eg bone fragment stuck in the mouth)

  • tumours

  • abscess

  • dental disease

  • kidney disease (can cause mouth ulcers)

  • ingestion of a caustic or irritating substance

  • ingestion of a foul tasting substance

  • burns (eg chewing on an electric cord)

  • neurological or functional disorder of the swallowing mechanism (eg tick toxicity)

  • pain

SALIVARy gland problems

  • foreign body (eg grass awn or splinter)

  • tumour

  • inflammation (sialoadenitis)

  • over-proliferation of cells (hyperplasia)

  • loss of blood supply (infarction)

  • salivary cyst (sialocele)

oesophageal and gastrointestinal Problems

  • Megaoesophagus

  • Oesophageal foreign body

  • Oesophageal tumour

  • Oesophageal inflammation (eg due to swallowing something caustic or irritating or from reflux of stomach acid)

  • Oesophageal stricture

  • Hiatal hernia (where the stomach bulges up into the chest cavity)

  • Bloated stomach

  • Gastric ulcer

  • Any problem that causes nausea (eg pancreatitis, parvo, intestinal foreign body)

metabolic problems

  • Hepatoencephalopathy (a consequence of severe liver disease)

  • Fever

  • Uraemia (a build up of toxins due to kidney failure)

  • Immune-mediated diseases

neurological problems

  • Botulism

  • Tetanus

  • Dysautonomia

  • Seizure

  • Nausea due to vestibular disease

Drugs and toxins

  • Caustic/corrosive toxins (eg cleaning products, petrol based products)

  • Bad tasting substances

  • Substances that stimulate salivation

  • Animal toxins (eg cane toads)

  • Irritant plants (eg poinsettia, daffodil bulbs)

  • Drugs or toxins that cause nausea


How do we make a diagnosis?

Our initial goal is to decide whether we have a serious cause of hypersalivation or not.

We’ll start with taking a thorough history including general health status, current medications, possible toxin exposure and other symptoms.

On physical examination we’re looking for signs of nausea (lip smacking, retching, food aversion), oral lesions. smelly breath and ability to swallow/gag (among other things).

If we’re concerned about a more serious cause (eg foreign body, liver disease), we are likely to suggest further investigation. This might involve blood/urine testing, X-rays and/or ultrasound.


How do we treat excessive salivation?

The treatment will depend on the cause. That said, we aren’t always able to identify the exact cause.

If we find a happy dog, who can eat fine and seems normal in other respects, we may not do anything more than suggest watchful waiting.

If we’ve identified the cause, we’ll treat that and the excess salivation should resolve. Rarely do we give specific medication to reduce saliva production.