Pandora released evils when she opened the container in Hesiod’s Greek myth.
Hesiod’s Works and Days describes a sealed storage jar containing destructive things that had previously been kept away from human beings. When Pandora opened it, the evils escaped and spread through the world. The myth therefore explains, in symbolic form, why sickness, hardship, and other suffering affect human life.
The familiar phrase “Pandora’s box” comes from a later Latin translation tradition. The Greek word pithos means a large jar or storage vessel, not a small box. Erasmus helped popularize the “box” wording in the 16th century, and that expression became standard in many languages.
The myth does not present the released contents as a single named disease or one specific object. “Evils” is the broad canonical description. The story also says that Hope remained inside the vessel, although scholars debate how that detail should be interpreted.