E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Sir Thomas Browne (Religio Medici, p. 67) rationalises this into hair-dye. The reference is to Medea renovating Æson, father of Jason, with the juices of a concoction made of sundry articles. After Æson had imbibed these juices, Ovid says: