Why is my dog drooling excessively at the dog park?

Excessive drooling in dogs at the dog park can be caused by excitement, stress, heat, or the presence of other dogs. It is a common reaction in some dogs and usually not a cause for concern. However, if the drooling is accompanied by other symptoms like lethargy or vomiting, it may be a sign of a more serious issue and you should consult a veterinarian.