Used primarily in the treatment of dry mouth (xerostomia), especially in patients with Sjögren's syndrome. It stimulates salivary flow by activating muscarinic receptors in the salivary glands. Also helps improve symptoms of dry eyes in some cases. Due to its ability to cross the blood-brain barrier, it may have effects on central nervous system functions, though this is not the primary therapeutic goal. Not commonly used in general dentistry but reserved for chronic, severe dry mouth conditions under medical supervision.