In the phrase “Pandora’s box,” what does the expression usually mean in modern English?

In modern English, “Pandora’s box” usually means a source of many troubles.

The expression comes from the Greek myth in which Pandora opens a container and releases evils into the world. English speakers use it figuratively for an action, decision, or discovery that creates numerous unexpected problems. A person may warn that investigating an old dispute or changing a complicated system could “open Pandora’s box.”

The idiom does not normally mean one single problem. Its force comes from the image of many difficulties emerging from one opening. That figurative sense is why the phrase appears in journalism, politics, law, science, and everyday conversation. It is often used as a warning about consequences that are difficult to control once they begin.

The expression also preserves a translation error or adaptation. Hesiod’s Greek story described a jar, not a box. The “box” became established through later Latin and European retellings, and the idiom retained that form even after scholars recognized the original vessel. Hope’s presence at the bottom of the jar is interpreted in different ways, but it is not part of the idiom’s ordinary definition.