Potassium permanganate drops are acidic drops that can treat inflammation of the vulva and improve the environment of the vagina to make it acidic, which prevents other bacteria from growing in the vagina. The pH of a normal vagina is usually less than 4.5 due to estrogen and lactobacillus, but if the vagina is infected by other bacteria, the pH of the vagina will rise. If a potassium permanganate bath is used at this time, it can increase the acidity of the vagina, thus improving the defense function of the vagina and preventing other pathogens from growing and reproducing in the vagina. So it has not only a therapeutic effect but also a defensive effect.