- In Dante’s Inferno Phlegethon is described as a river of blood that boils souls
- It is in the Seventh Circle of Hell, which punishes those who committed crimes of violence against their fellow men; murderers, tyrants, and the like
- By causing hot blood to flow through their violent deeds in life, they are now sunk in the flowing, boiling blood of the Phlegethon
- The depth at which each sinner must stand in the river is determined by the level of violence they caused in life, centaurs patrol the circle, firing arrows at those who try to rise above their allotted level in the river
- Dante and Vergil cross Phlegethon with help from Nessus