What does the modern idiom “Pandora’s box” describe?

The modern idiom “Pandora’s box” describes a source of many troubles or complicated problems. It comes from the Greek myth in which opening Pandora’s container releases miseries into the human world.

In everyday English, opening a Pandora’s box means starting an action that produces numerous unexpected difficulties. The expression can apply to politics, technology, family disputes, investigations, or any situation where one decision unleashes consequences that are hard to control.

The idiom is based on a later wording rather than Hesiod’s original description. Hesiod wrote about a jar, not a box, and the English phrase became established through translation and retelling. The expression is therefore both a reference to the myth and a general metaphor for an apparently simple act with wide-ranging harmful effects.