If your dog is suddenly drooling excessively, there's a good chance that something is wrong. Excessive drooling in dogs, or hypersalivation, can be caused by many different things, from neurological disorders to oral cancer. In this article, we will discuss the top 7 reasons why your dog might be drooling excessively. Treatment and prognosis depend on the underlying cause, so it's important to get your dog checked out by a veterinarian as soon as possible if you notice excessive drooling and salivating.

1. Idiopathic Trigeminal Neuritis

Idiopathic trigeminal neuritis is a condition that results in inflammation of the trigeminal nerve. This cranial nerve is responsible for sensations in the face, including the tongue and mouth and jaw movement. Dogs with idiopathic trigeminal neuritis may drool excessively and have difficulty eating and drinking as one of the functions of the trigeminal nerve is to open and close the jaw. There is no cure for this condition, but treatment can help relieve symptoms.

2. Facial Nerve Paralysis

Facial nerve paralysis can occur when the facial nerve is damaged or compressed. This can result in difficulty moving the muscles of the face, including those used for chewing and swallowing. There are a variety of causes of facial nerve paralysis in dogs but idiopathic facial nerve paralysis (similar to Bell's palsy in people) is the most common. Dogs with facial nerve paralysis may drool excessively and have trouble eating and drinking.

3. Toxins

There are many different toxins that can cause excessive drooling in dogs. Some common examples include insecticides, plants, and chemicals. If you suspect your dog has been exposed to a toxin, it is important to seek veterinary care immediately as some toxins can be very dangerous. The most common class of toxins that cause excessive drooling in dogs are insecticides, and this occurs mainly from the cholinergic effects of these toxins, as opposed to a direct caustic effect on the mouth like certain plants and chemicals.

4. Oral Foreign Objects

Oral foreign bodies are another common cause of excessive drooling in dogs. Dogs will often chew on things they shouldn't, and sometimes these things can get stuck in their mouths. A common location for bones and sticks to become stuck are between the upper left and right molars. Sudden malodorous breath can also be a side of a foreign object that is stuck in the mouth. If you think your dog may have swallowed a foreign object, it is important to take them to the vet right away as they may need heavy sedation to remove the object. Common foreign objects include bones, sticks and toys.

5. Oral Cancer and Masses

Oral cancer is another possible cause of excessive drooling in dogs. Oral cancer can occur in any area of the mouth. Dogs with oral cancer may drool excessively, have difficulty eating and drinking, and may also have bad breath. Treatment for oral cancer depends on the stage of the disease and the type of cancer or mass that is present.

6. Hepatic Encephalopathy

Hepatic encephalopathy is a condition that can occur in dogs with liver disease. This condition results in changes in the brain and can lead to seizures, excessive drooling, and even coma. If your dog has been diagnosed with liver disease, it is important to talk to your veterinarian about whether he or she is at risk for hepatic encephalopathy. Dogs with hepatic encephalopathy drool excessively due to the build of toxins in the bloodstream that causes hepatic encephalopathy.

7. Dental Disease and Tooth Fractures

Dental disease is among the most common cause of excessive drooling in dogs. Dogs with dental disease often have bad breath, and they may drool excessively from the mouth as a result of the pain associated with the disease. Untreated dental disease can lead to more serious health problems, so it is important to get your dog's teeth checked by a veterinarian on a regular basis. Dental disease can also cause tooth fractures, which can be very painful for the dog and can also lead to excessive drooling.


Excessive drooling in dogs and hypersalivation can have many different causes. The most common are trigeminal neuritis, facial nerve paralysis, toxins, oral foreign objects, and dental disease or tooth fractures. Let your veterinarian know if you see any of these symptoms so they can help diagnose the cause and get treatment going for your pup!