Vaginitis is defined as inflammation or infection of the vagina and is associated with a spectrum of symptoms, including vulvovaginal itching, burning, irritation, dyspareunia, "fishy" vaginal odor, and abnormal vaginal discharge. Vaginal symptoms are some of the most frequent reasons for patient visits to obstetrician-gynecologists () and may have important consequences in terms of discomfort and pain, days lost from school or work, sexual functioning, and self-image (). Distinguishing vaginal from vulvar symptoms is important to direct evaluation and treatment. The purpose of this document is to provide updated evidence-based guidance for the diagnosis and treatment of the common causes of vaginitis in nonpregnant patients. Information on the treatment of vaginitis in patients with human immunodeficiency virus (HIV) is covered elsewhere (). Guidelines are subject to change. For the most up-to-date information on vaginitis diagnosis and treatment, see the Centers for Disease Control and Prevention (CDC) Sexually Transmitted Diseases webpage, which is available at https://www.cdc.gov/std/.