Recurring yeast and bacterial vaginosis infections happen when the natural balance of bacteria and yeast in the vagina is disturbed. This can be caused by hormonal changes, tight clothing, or scented products. To prevent them, keep the area clean and dry, wear cotton underwear, avoid douching or perfumed soaps, and eat probiotic-rich foods like curd or yoghurt. See a gynecologist for proper treatment and to check for underlying causes.