There are a few things that can cause your dog to drool excessively.
Dogs will drool if they feel nauseated but not to the point of vomiting. A change in diet could be the underlying cause.
They will also drool if they have mouth pain from a possible tooth or gum problem. Take a look in his mouth but you might not see anything. Sometimes tooth pain is not noticeable.
Sometimes they will drool if they have ingested garbage or other irritants and will drool if they have ingested poison.
If this just started, you can just watch it and see if it gets better on its own.
If not, a vet could quickly diagnose it for you.
I would not use any medication unless you can pinpoint the cause.
Let me know if you have more questions.