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; though in Homer's poems nectar is usually the drink and ambrosia the food of the gods; it was with ambrosia Hera "cleansed all defilement from her lovely flesh", and with ambrosia Athena prepared Penelope in her sleep, so that when she appeared for the final time before her suitors, the effects of years had been stripped away, and they were inflamed with passion at the sight of her. On the other hand, in Alcman, sector is the food, and in Sappho and Anaxandrides, ambrosia is the drink. When 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 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 had not blood in their veins, but ichor.
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."