"Purge the Poison" is a song written and recorded by Welsh singer-songwriter Marina for her fifth studio album, Ancient Dreams in a Modern Land (2021). It was released as the project's second single on 14 April 2021, through Atlantic Records, alongside the album's announcement. The song was produced by Jennifer Decilveo and previously teased by Marina in 2020. It was promoted through the creation of a news alert website called AllMyFriendsAreWitches.com. The song is a guitar-heavy pop, electropop, and power pop anthem, sung from the point-of-view of Mother Nature. Its lyrics preach about a better society, that is free of capitalism, climate change, and patriarchy.