In the ancient Greek myths, ambrosia (Greek: ἀμβροσία, "immortality") is sometimes the food or drink of the Greek gods, often depicted as conferring longevity or immortality upon whoever consumed it. It was brought to the gods in Olympus by doves, so it may have been thought of in the Homeric tradition as a kind of divine exhalation of the Earth.
Ambrosia is very closely related to the gods' other form of sustenance, nectar. The two terms may not have originally been distinguished. In Homer 's poems, nectar is usually the drink and ambrosia is the food of meals involving gods. On the other hand, in Alcman, nectar is the food, and in Sappho and Anaxandrides, ambrosia is the drink. Both descriptions, however, could be correct as Ambrosia could be a liquid that is considered a meal (much like how soup is labeled the same).
The consumption of ambrosia was typically reserved for divine beings. Upon his assumption into immortality on Olympus, Heracles is given ambrosia by Athena, while the hero Tydeus is denied the same thing when the goddess discovers him eating human brains. In one version of the myth of Tantalus, part of Tantalus' crime is that after tasting ambrosia himself, he attempts to steal some away to give to other mortals. Those who consume ambrosia typically didn't have blood in their veins, but instead ichor.
Hera used ambrosia to "cleanse all defilement from her lovely flesh", and Athena used ambrosia to prepare Penelope in her sleep to strip away the effects of aging, and so that when she appeared for the final time before her suitors they would be inflamed with passion at the sight of her. A character in Aristophanes' Knights says, "I dreamed the goddess poured ambrosia over your head—out of a ladle," the homely and realistic ladle brings the ineffable moment to ground with a thump.
Both nectar and ambrosia are fragrant, and may be used as perfume: in the Odyssey Menelaus and his men are disguised as seals in untanned seal skins, "and the deadly smell of the seal skins vexed us sore; but the goddess saved us; she brought ambrosia and put it under our nostrils."