In the story the Odyssey, Hermes gave this herb to Odysseus to protect him from Circe's wizardry when he went to her palace to rescue his friends. These friends came together with him from the island Aiolos after they escaped from the Laestrygonians.
According to the "New History" of Ptolemy Hephaestion (according to Photius) the plant mentioned by Homer grew from the blood of the Giant killed on Circe's island, by Helios ally of Circe. In this description the flower was white, and a derivation of the name was given, from the "hard" (Greek malos) combat with the Giant.
Homer also describes Moly by saying "The root was black, while the flower was as white as milk; the gods call it Moly, Dangerous for a mortal man to pluck from the soil, but not for the deathless gods. All lies within their power".
There has been much controversy as to the identification. Philippe Champault decides in favour of the Peganum harmala (of the order Rutaceae), the Syrian or African rue (Greek πἠγανον), from the husks of which the vegetable alkaloid harmaline is extracted. The flowers are white with green stripes. Victor Bérard relying partly on a Semitic root, prefers the Atriplex halimus (atriplex, a Latin form of Greek ἀτράφαξυς, and ἅλιμος, marine), order Chenopodiaceae, a herb or low shrub common on the south European coasts. These identifications are noticed by R. M. Henry, who illustrates the Homeric account by passages in the Paris and Leiden magical papyri, and argues that moly is probably a magical name, derived perhaps from Phoenician or Egyptian sources, for a plant which cannot be certainly identified. He shows that the "difficulty of pulling up" the plant is not a merely physical one, but rather connected with the peculiar powers claimed by magicians.
Medical historians have speculated that the transformation to pigs was not intended literally but refers to anticholinergic intoxication. Symptoms include amnesia, hallucinations, and delusions - this description of "moly" fits the snowdrop, a flower of the region that contains galantamine, which is an anticholinesterase and can therefore counteract anticholinergics.