Why do dogs drool? In simple terms, excessive drooling in dogs happens because dogs either produce too much saliva or do not swallow the saliva they produce. Unfortunately, there are a wide variety of reasons for both excess saliva production and decreased swallowing. Because stopping a dog from drooling requires knowing the root cause of the problem, finding an effective treatment for excessive drooling is a potentially difficult task.
Conformation of the Lips
Some dogs have extra skin on their upper lips. This pendulous skin does not cause them to produce excess saliva, but it does cause more of the saliva they produce to leak out of their mouths. This issue is especially common in giant-breed dogs including the Newfoundland, mastiff, Great Dane and others.
Fear and Anxiety
Fearful or anxious dogs may drool excessively. This usually occurs when something is frightening or upsetting the affected dog and resolves when the stimulus for the fear or anxiety is removed. For example, a dog with separation anxiety might drool when its owner is about to leave or during the time the owner is gone.
Anticipation of Food
It is normal for dogs to drool when they smell food or anticipate being fed. Some dogs begin to associate owner behaviors that precede feeding with the food itself. These dogs may drool when they hear the owner opening a can or rustling a bag, see the owner opening a cabinet or the refrigerator or witness some other behavior. This is normal and no reason for concern.
Bitter or Unpleasant Tastes
Dogs often drool when they taste something bitter or unpleasant. Drooling caused by an unpleasant taste should resolve soon after the offending substance leaves the mouth.
Irritation of the stomach and intestines causes increased salivation due to activation of certain receptors in the gastrointestinal tract. While drooling does not necessarily mean a dog is about to vomit, dogs often drool profusely before they vomit.
Drooling is a common symptom of motion sickness in dogs. When dogs drool due to motion sickness, the hypersalivation only occurs when the animal is travelling in a moving vehicle. A dog that is drooling excessively at other times likely does not suffer from motion sickness or suffers from another health issue in addition to its motion sickness.
Increased production of saliva is a normal response to irritation inside the mouth. Common causes of oral irritation in dogs include the following:
- Gum disease.
- Oral ulcers.
- Dental disease.
- Foreign bodies in the mouth.
- Oral tumors.
- Ingestion of caustic chemicals, plants or other irritating substances.
- Insect stings or bites in the mouth.
- Burns in the mouth.
- Injuries in the mouth.
- Oral abscesses.
Toxins or Drugs
Certain medications and toxic substances cause hypersalivation in dogs. Some of these include the following:
- Snail baits.
- Other insecticides.
- Toxic mushrooms.
- Boric acid.
- Venom from animals, like black widow spiders and scorpions.
- The secretions of some toads and salamanders.
- Many toxic plants.
Other Potential Causes of Drooling
While the causes discussed above are among the most common reasons for drooling in dogs, the condition also has a number of other possible causes including the following:
- Metabolic diseases, including kidney disease.
- Swallowing disorders.
- Salivary gland abscesses, cysts or tumors.
- Neurological disorders.
- Infectious diseases, including rabies.
Treatment for a Dog Drooling Excessively
Successful treatment of drooling requires identifying and correcting its cause. For example, reducing drooling that is due to conformational issues may require surgery to reshape the lips while solving drooling caused by anxiety requires relieving the anxiety. Talk to your veterinarian about the best way to address your dog’s excessive drooling.
- Animal Poison Contro at the ASPCA.
- Behavioral Problems of Dogs From the Merck Veterinary Manual.
- Brunker, Jill. “Ptyalism.” Small Animal Medical Diagnosis. Ed. Lorenz, et al. Ames, Iowa: Wiley-Blackwell, 2009.
- Salivary Disorders in Small Animals from the Merck Veterinary Manual.