In the modern expression “Pandora’s box,” what does opening it usually symbolize?

In the modern expression “Pandora’s box,” opening it usually symbolizes unleashing unforeseen troubles.

The idiom comes from the Greek myth in which Pandora opens a sealed container and releases diseases, hardships, and other evils into the human world. In contemporary English, the phrase is normally used figuratively for an action that creates many unexpected problems or consequences that are difficult to control.

The expression does not usually refer to one particular object. It can describe a controversial investigation, a risky technological experiment, a legal decision, or any choice whose consequences multiply after it is made. The important idea is irreversibility: once the contents are released, restoring the earlier situation is difficult or impossible.

The common phrase also preserves a historical translation error. Hesiod’s vessel was a pithos, or storage jar. Erasmus’s Latin wording helped establish the “box” version in European languages, and that version became the standard English idiom.