Burning mouth syndrome (BMS) is a burning, tingling or scalding sensation in the mouth, lasting for at least four to six months, with no underlying known dental or medical cause. No related SIGNS OF THE DISEASE  are found in the mouth. People with burning mouth syndrome may also have a subjective XEROSTOMIA ,PARAESTHESIA or an altered sense of taste or smell. The International Association for the Study of Pain defines burning mouth syndrome as "a distinctive nosological entity characterized by unremitting oral burning or similar pain in the absence of detectable mucosal  changes"^[  and "burning pain in the tongue or other oral mucous membranes", and the international Headache Society defines it as "an intra-oral burning sensation for which no medical or dental cause can be found". To ensure the correct diagnosis of burning mouth syndrome, Research Diagnostic Criteria (RDC/BMS) have been developed.Insufficient evidence leaves it unclear if effective treatments exist. For this special issue we are very interested in studies dealing with the physiological mechanisms involved and any novel treatments.