The modern English phrase is “Pandora’s box,” meaning a source of many troubles.
In everyday English, opening a Pandora’s box means beginning an action that creates a cascade of unexpected problems. The expression comes from the myth in which Pandora opens a container and releases evils into the world, leaving Hope inside. It is now used for political decisions, scientific discoveries, legal disputes, and other situations with difficult consequences.
The phrase is historically a translation and adaptation rather than the exact wording of Hesiod. The ancient Greek story describes a pithos, or large storage jar. The “box” version became influential through later Latin and European retellings, and English eventually made it the standard expression.
The phrase is sometimes used simply to mean “a complicated problem,” but its stronger sense involves consequences unleashed by an apparently small act. It does not specifically mean a secret treasure chest or a literal box.