Any substance that inhibits the growth of fungal spores. Lubricant manufacturers use fungicides to prevent overgrowth of harmful yeasts, including Candida albicans, the fungus responsible for yeast infections.

Natural fungicides include the oils of the teatrea, jojoba, cinnamon, rosemary, and neem plants. While fungicides may decrease the chances of a yeast infection, they do not prevent most types of sexually transmitted infections (STIs).