Many boxers drool because their loose lips and jowls allow saliva to escape, especially after the dog eats or drinks. Excessive drooling, however, can also be a sign of a health problem.
All dogs drool to some degree, especially when they are panting or right after eating or drinking. Excessive drooling is a common symptom of mouth pain due to dental problems like abscessed teeth. According to WebMD, it can also be a symptom of certain serious diseases like rabies, distemper or heat stroke. Dogs who suddenly start drooling excessively should be examined by a veterinarian as soon as possible.