In the standard idiom, what does “to open Pandora’s box” mean?

“To open Pandora’s box” means to unleash unforeseen problems or complications.

The idiom comes from the myth in which opening a sealed container releases suffering into the human world. In modern English, it describes an action that begins a chain of difficult consequences, especially when those consequences are hard to reverse. The expression is used in journalism, politics, law, science, and everyday conversation.

The phrase does not literally require a physical box, nor does it necessarily refer to intentional wrongdoing. Someone can “open Pandora’s box” by asking a question, changing a rule, or revealing information that leads to wider complications. The essential idea is that a seemingly limited action produces many problems.

The idiom also preserves the translation history of the myth. Hesiod’s original container was a jar, while the box image came from a later Latin translation. “Hope remained” is another mythological detail, but it is not part of the idiom’s usual definition.