Just like Candida, hydrogen peroxide is already present in the vagina. It is already there doing its job of keeping the yeast infection at bay. However, the. Jump to Hydrogen peroxide - Hydrogen peroxide. Hydrogen peroxide is a bacteria and yeast-killing antiseptic, according to lab studies. While it won't work on every species of yeast, some women swear by using hydrogen peroxide topically when they get a yeast infection.