How old is your dog?
Does she eat dry or canned food?
Does she seem to struggle at all with the food lately even if she does eat it?
Have you looked inside her mouth? is there an odor, a lot of build up on the back teeth, and bleeding, swelling, or ulcers that you can tell?
There are two issues that can occur in this age dog that would increase drooling. A fractured tooth. This can occur when a dog chews on hard objects like bones, ice, and even some toys. A slab fracture can occur where the side of the tooth literally shears off. Many times this isn't noticeable to the naked eye. Another common condition is an inflammation or infection of the salivary gland which can cause an increase in drooling. If the drooling doesn't decrease or you notice other symptoms like not eating or swelling around the snout then I would have her examined by your veterinarian. Without other symptoms present at this time I wouldn't be overly concerned.