Saliva plays a key role in maintaining oral homeostasis, function, and health. The prevalence of xerostomia and its consequences are rising due to the increasing aging population, the effects of some systemic diseases, medical management, and commonly-prescribed medications that reduce saliva production. When salivary function is diminished, patients are at a greater risk of developing caries, discomfort in wearing dentures, and opportunistic diseases, such as candidiasis. The psychosocial aspects of xerostomia can range from a mild effect on self-rated oral health to frustration, embarrassment, unhappiness, or substantial disruptions in quality of life. This article reviews the clinical features, diagnosis, and prevalence of dry mouth, as well as its treatment strategies.