What English expression describes an action that releases many unforeseen troubles, like Pandora’s container?

“Opening Pandora’s box” describes an action that releases many unforeseen troubles. The expression comes from the myth in which Pandora opens a container and evils spread into the human world.

In modern English, the phrase is usually applied to a decision or investigation that creates consequences far greater than expected. It can describe political controversies, scientific risks, legal disputes, or personal situations. The key idea is not merely curiosity but the unleashing of problems that are difficult to control or reverse.

The expression developed from the myth’s later “box” tradition, although Hesiod described a pithos, or storage jar. Renaissance translations and retellings helped establish the box wording in European languages, and the phrase later became a standard English idiom.

It is often confused with “opening a can of worms,” which has a similar meaning but a different origin. “Opening Pandora’s box” specifically invokes the Greek myth and usually carries a stronger sense of hidden consequences.