Excessive drooling in dogs is not always a sign of a medical issue. It could also be because of the type of breed or sensing food. It becomes a potential cause of a medical problem if they have dental issues, injuries, infections, mouth or lip discomfort, and objects lodged in the throat, mouth, or teeth. Abnormal drooling in dogs may also indicate that your dog has heatstroke or swallowed a poison or toxin.