In the Greek myth of Pandora's jar, evils escaped into the world when it was opened.
Hesiod describes Pandora lifting the lid of a storage jar, after which destructive troubles spread among humanity. The myth uses the event to explain why mortal life contains suffering, disease, exhausting labor, and other hardships. The evils are presented as previously kept away from human beings.
The familiar English phrase “Pandora's box” comes from a later translation tradition. Hesiod's original object was a pithos, a large jar, not a small box. This difference matters because the jar was a recognizable household and agricultural storage vessel in the ancient Mediterranean.
The myth does not provide a modern scientific explanation for illness or disaster. It is a traditional etiological story: a narrative that explains why an important feature of human life exists. Later writers and artists have expanded the list of released evils, but the central image remains the same.