Dogs may salivate more often around other dogs because they are anxious or excited. Excess salivation in dogs can be stress-related, which can often be triggered by excitement or fear in response to outside stimuli. A higher level of salivation corresponds to a higher level of anxiety.
Anxiety in dogs is common. Socialization can help reduce fear and anxiety and increase confidence. Exposure to various sights and sounds can lower a dog's anxiety significantly. If anxiety is severe or persistent, a veterinarian may prescribe medication to treat it.
Ptyalism is also a condition in dogs that is characterized by excessive drooling. While anxiety is one cause, ptyalism can indicate serious health problems, such as oral and pharyngeal diseases, salivary diseases, metabolic disorders and neurological disorders. It may also indicate exposure to drugs or toxins. In order to determine whether or not a dog's excessive salivation is a medical concern, an evaluation by a veterinarian is recommended.
Some breeds, such as the Mastiff and Saint Bernard, are known for excessive drooling. This is not necessarily because these breeds salivate more than other breeds, but that their loose jowls allow the drool to leak out more and their large stature makes the drool more noticeable.