The English phrase “Pandora’s box” describes a source of new problems opened by an action.
In everyday English, opening Pandora’s box means starting a process that releases many unexpected complications. The expression comes from the myth in which Pandora opens a sealed container and troubles spread into the human world. It is now used for political decisions, technological experiments, legal disputes, and other situations in which consequences are difficult to contain.
The phrase is also a translation-based transformation of the ancient story. Hesiod described a pithos, a large storage jar or vessel, rather than a small box. The Renaissance scholar Erasmus helped popularize the “box” form in Latin discussions, and English usage later made it familiar.
“Pandora’s box” is often used figuratively rather than as the name of a physical object. It should not be confused with “Achilles’ heel,” which means a vulnerable point, or the “Midas touch,” which refers to apparently effortless success. Those expressions come from different Greek myths.