Hot flashes, which are sudden, temporary intense sensations of body warmth, often accompanied by flushing and sweating during the day and night (night sweats), are referred to as vasomotor symptoms (VMS). These VMS are associated with sleep disturbances, cognitive dysfunction, severe fatigue, increased pain severity and decreased quality of life. Hot flashes affect up to 80% of women going through the menopause transition, 80% of men with prostate cancer undergoing or after completion of androgen deprivation therapy and 50–80% of breast cancer patients receiving hormone deprivation therapy.