What does the English expression “to open Pandora’s box” usually mean?

The English expression “to open Pandora’s box” usually means to unleash many problems.

The idiom comes from the myth in which Pandora opens a sealed container and releases sickness, hardship, and other troubles into the human world. In modern English, it is used figuratively when an action creates a chain of difficult or harmful consequences that cannot easily be reversed.

The expression does not normally refer to one isolated problem. Its force comes from the idea that opening the container releases many separate troubles at once. Writers may use it in politics, science, technology, family disputes, or business. The idiom also preserves the myth’s association with curiosity and irreversible consequences, even though the earliest Greek account calls the container a jar rather than a box.