Excessive Drool Remedies

Does anyone have success using an herb that would cause dry mouth to reduce salivation in a dog such as a mastiff, where the salivation is not a medical emergency? Or perhaps an antihistamine?

what can cause over excessive drooling from a dog?

EC: Helpful Websites
http://www.metpet.com/Reference/Dogs/Health/dog_drooling.htm
http://www.associatedcontent.com/article/46491/decrease_your_dogs_excessive_drooling.html
http://www.ehow.com/how_2251674_diagnose-excessive-drooling-dog.html

For sudden, excessive drooling: http://answers.yahoo.com/question/index?qid=20061007172953AAD3q1d