A Greek myth concerning a wonder-working juice which confers immortality. However, when asking that Tithonus be granted eternal life they forgot to mention eternal youth, which meant he suffered eternal old age.
So, keep drinking the wheat-grass and carrot wonder-working juices by all means, but be careful what you ask for.
‘I am the supplier of that wonder-working juice that Memnon’s daughter used for prolonging the life of her grandfather Tithonus’…
Note: it appears to have been Memnon’s mother, Aurora, rather than his daughter (he didn’t have any); perhaps a memory lapse on the part of Folly, or her chronicler, Erasmus.
Source: Desiderius Erasmus (1469-1536), Praise of Folly, trans. Roger Clarke (Richmond: Oneworld Classics, 2008 (1511)), p. 19