Evaluation of patients complaining of dry mouth symptoms is difficult because it is a common complaint with a variety of causes including Sjögren’s syndrome and several possible means of assessment. Classification and diagnostic criteria of dry mouth have not been established yet, and an establishment of those is thus strongly requested. In this review, “Classification of xerostomia(dry mouth)”proposed by The Committee for Terms and Classifications, The Japanese Association for Oral Mucosal Membrane was introduced and its course and issues were also explained. Furthermore, various approaches to develop novel clinical and laboratory tests, which are useful in the differential diagnosis of dry mouth, were introduces and those future aspects were described.
