Dealing with Drooling

By Courtney Barnes, BSc, DVM; Malcolm Weir, DVM, MSc, MPH; Lynn Buzhardt, DVM

What is drool?

Dogs, like people, produce a thick liquid inside their mouths called saliva (drool). Saliva is composed of 98% water, but also contains antibacterial compounds, enzymes, and electrolytes that are important to overall health. Glands near the jaw produce this enzyme-rich juice that empties into the mouth through ducts.

  • Saliva contains an enzyme called amylase that initiates the digestive process. Amylase mixes with food during chewing and breaks down food matter. 
  • Saliva moistens chewed food and helps form a bolus that aids in swallowing. 
  • Saliva constantly lubricates the mouth, which improves the sense of taste. Plus, a moist mouth is more comfortable than a dry one.
  • Saliva promotes dental health by bathing the teeth with proteins and minerals that protect tooth enamel and reduce gum disease. 
  • Saliva decreases the formation of cavities and prevents tooth decay by clearing food particles from the teeth. 
  • Saliva has antibacterial properties that decrease germs in the mouth that cause bad breath.

Overall, saliva is a good thing. But too much of a good thing can be bad. While the production of saliva is normal, excessive production is not. When excess saliva is produced, the dog does not swallow it all. The saliva overloads the mouth, runs over the brim, and the dog drools.

Why do dogs drool?

There are many causes of drooling (hypersalivation). Some are normal and some indicate health problems.

Food response: When you smell bacon frying or cookies baking, you may salivate. Your dog has over 200 million scent receptors, so he experiences an even greater reaction when he smells your food, his food, or even when he hears you open the dog food bag.

Nausea: No one likes to be nauseated, whether it’s due to gastrointestinal disturbances, vestibular (balance) problems, or car sickness. When nauseated, a dog’s salivary glands go into overdrive and he drools.

Physiology: Some dogs’ mouths produce saliva normally, but the saliva appears excessive because their mouth anatomy allows the liquid to dribble out. Giant breeds are known for their saggy lips and drooping jowls that do not effectively hold saliva in and allow the liquid to run out. Some of the “drooling breeds” include the bloodhound, mastiff, St. Bernard, and Newfoundland dogs.

Foreign bodies: When a dog gets something trapped in his mouth (e.g., wood fragment or plant matter), he drools. The offending object may be wedged between the teeth, often lying across the roof of the mouth, or embedded in the gum tissue. Dogs do not floss, so this is a common cause of drooling.

Dental problems: Although saliva helps protect the teeth, dogs still develop dental issues. Tartar traps bacteria and leads to gingivitis and periodontal disease. Inflamed or infected gums become sore, and teeth become loose in the sockets as bony tissue erodes. Teeth may fall out or fracture, which can be painful. All these dental problems result in hypersalivation.

Injuries: Abrasions from chewing hard objects, ulcers, cuts, and burns can cause excess drooling.

Growths: Lumps or bumps in the mouth can cause drooling. These growths may be benign warts or cancerous tumors. Even harmless growths can result in drooling.

Caustic agents: If your dog licks or eats something caustic or acidic, he may drool excessively. Think about tasting lemon juice. Dogs are curious and often lap up household cleaners or snatch a lemon from the trash or nibble on a plant. All these things can irritate the lining of the mouth and cause drooling.

Gastrointestinal (GI) problems: Gastric reflux may send nasty fluids back up the esophagus and into the mouth, which results in hypersalivation. Certain physical problems, such as hiatal hernias (stomach herniating into the esophagus) and megaesophagus (enlarged esophagus) can lead to reflux.

Excitement: Some dogs drool when they get excited or agitated – which is why they may drool on your guests!

What other symptoms might appear with drooling?

Drooling may be a symptom of an underlying problem. Here are a few other signs that may accompany hypersalivation:

Decreased appetite: If hypersalivation is caused by chronic GI problems, the dog may experience a gradual loss of appetite. If nausea is the cause, the drooling may be temporary and cease when the upset stomach resolves. If the dog is drooling because of a mouth injury, dental disease, growth, or foreign body, the drooling will not stop until the physical condition heals, or the offending item/growth is removed. If the problem is dental disease, the appetite will not return until the oral issues are handled (i.e., teeth cleaned, teeth extracted, and/or gum infection cleared).

Changes in eating routine: Dogs that love dry kibble may hesitate to eat when their mouths are sore. They may take small bites and chew cautiously, often on the least affected side. They may hold their head at an odd angle to position the food on the less painful side and may drop food from their mouths. They often eat better when served soft, moistened food.

Changes in behavior: Even the sweetest dog may become aggressive when in pain. Other dogs become reclusive and withdrawn when they are hurting.

Pawing at the face: To alleviate oral pain, some dogs rub their muzzle on the floor or rub it with their paws.

Difficulty swallowing. Drooling dogs with esophageal or stomach problems may gulp or extend their necks when they swallow food or water.

How is the cause of drooling diagnosed?

When investigating the cause of your dog’s drooling, your veterinarian will start with a complete physical exam, paying particular attention to the mouth. A simple survey of the oral cavity may point to a diagnosis and treatment plan. If the cause of drooling is not clear, your veterinarian may suggest blood tests, X-rays (radiographs), or other diagnostic tests.

What is the treatment for drooling?

With so many possible causes of drooling, treatment plans will vary. Treating the underlying cause may include cleaning teeth, extracting teeth, removing growths, treating GI problems, avoiding irritants, healing injuries, removing foreign objects, or giving medication for nausea before you take a car trip.

If the cause is behavioral, try settling your dog down before allowing guests to enter the house, or place the dog in a quiet area while you entertain visitors. Be ready for drooling when you cook dinner by having a towel handy to mop up the deluge.

If the cause is due to the shape of your dog’s mouth, there is not much that can be done. Try tying a trendy bandana on your dog to catch the slobber. Skin irritation and infection can occur from the prolonged moisture, so keep the fur clipped and bathe the chin and neck regularly. After that – enjoy those wet kisses.

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