In modern English, what does “Pandora’s box” usually describe?

In modern English, “Pandora’s box” usually describes a source of unexpected troubles. The expression is used when an action, discovery, or decision releases many difficult consequences that are hard to control.

The idiom comes from the Greek myth in which Pandora opens a sealed vessel and allows evils to spread through the human world. The story gives the phrase its central image: one apparently limited act produces a cascade of problems.

The expression does not normally refer to a literal container, and it is not restricted to mythology. Newspapers, books, politics, science, and everyday conversation use it metaphorically for situations that reveal complications after being opened or investigated.

Although the phrase emphasizes danger, the original story also includes Hope. That surviving element gives the myth a more complicated ending than the idiom often suggests, since the narrative includes both suffering and the possibility of endurance.