Menstrual disorders are a major reason for gynaecological consultations worldwide and, unfortunately there are many different definitions and classifications of this condition. Clear definitions and terminology are necessary for scientific literature, particularly for clinicians, and for clinical trials comparing two treatments. The International Federation of Gynaecology and Obstetrics (FIGO) Menstrual Disorders Working Group has proposed abandoning the use of one common term, dysfunctional uterine bleeding (DUB), while continuing to use the terms abnormal uterine bleeding (AUB) and heavy menstrual bleeding (HMB). Furthermore, the group issued the PALM-COEIN classification system for menstrual disorders, which has quickly been adopted around the world. The PALM-COEIN system allows clinicians and researchers to identify and classify women with both AUB and HMB in a systematic manner, provides reliable information for research purposes and for epidemiological and prevalence studies in different settings, and supports accurate diagnoses and treatment. Additionally, this classification system is useful for selecting treatments appropriate for different stages of women's reproductive years and for different patterns of menstrual bleeding. Among the proposed treatments are the use of combined oral contraceptives, the levonorgestrel-releasing intrauterine system, tranexamic acid, mefenamic acid, and other nonsteroidal anti-inflammatory drugs (NSAIDs).