CERBERUS, in fabulous history, a dreadful three-headed monster, born of Typhon and Echidna, and placed to guard the gates of hell. He fawned upon those who entered, but devoured all who attempted to get back. He was, however, mastered by Hercules, who dragged him up to the earth, when, in struggling, a foam dropped from his mouth, which produced the poisonous herb called aconite or wolf's-bane.