A use of isomaltulose in the preparation of a vaginal composition, wherein the amount of isomaltulose used is 0.05-20% (w/w). A vaginal composition contains 0.05-20% (w/w) of isomaltulose. The composition may be a health product, health care product, cleaning product, skin care product, deodorant, cosmetic, or disinfectant composition or a pharmaceutical composition. A non-therapeutic vaginal care method, a non-therapeutic vaginal cleaning method, a method for improving vaginal acidity, a method for promoting growth of Lactobacillus in the vagina, and a method for preventing and treating vaginal dysbacteriosis, especially bacterial vaginal diseases, these methods being implemented by administering the composition to women's vagina.