The aims and purposes of this systematic review of the international literature are to discuss and clarify some considerations on Burning Mouth Syndrome (BMS). Over the last 40 years, many researchers have addressed this disease clinically or experimentally. Thus, the etiology and pathogenesis of BMS remain unclear. We analyzed the etiopathogenesis of Burning Mouth Syndrome and of the burning oral sensation and currently, we could not find a consensus on the diagnosis and classification of BMS. Further studies are required to better understand the pathogenesis of BMS, and a "Gold Standard" classification is required because not every burning sensation in the mouth is BMS.