When women suffer from vaginal dryness, the vaginal ecological environment has changed from moist to dry. This change can drive an ecological shift in dominant vaginal bacterial flora. For example, if a river dries, fish would die and other life forms that can accommodate low water and dried land, such as amphibians, may thrive. This is called an ecological shift. When such a shift occurs in the vaginal ecology, bacterial vaginosis (BV) occurs and it can cause a pungent fishy odor.