In response. Yes.
Regular douche is nothing more than vinegar. Yeast is slightly sweet, and is therefore acidic. Vinegar kills germs on counter tops because of its strong acidity. Vinegar that can kill germs will kill yeast.
Hydrogen peroxide is an anti-septic, which means it can also kill germs, and as a germ killer, it is also a yeast killer. The indication that the yeast has been killed is when the yeast infested area stops itching.