So he spoke, and they cried aloud, and called to her. And she straightway came forth and opened the bright doors, and bade them in; and all went with her in their folly. Only Eurylochus remained behind, for he suspected that there was a snare. She brought them in and made them sit on chairs and seats, and made for them a potion of cheese and barley meal and yellow honey with Pramnian wine; but in the food she mixed baneful drugs, that they might utterly forget their native land. Now when she had given them the potion, and they had drunk it off, then she presently smote them with her wand, and penned them in the sties. And they had the heads, and voice, and bristles, and shape of swine, but their minds remained unchanged even as before. So they were penned there weeping, and before them Circe flung mast and acorns, and the fruit of the cornel tree, to eat, such things as wallowing swine are wont to feed upon. (Odyssey 10.229-243; trans. A. T. Murray)
The mixed drink mentioned above would be instantly recognizable to Greek readers as kykeon (cf. Iliad 9:638-641), a ritual drunk used in the Eleusinian Mysteries, and one that has long been suspected of containing psychoactive compounds, either intentionally or through contamination of the barley by ergot. However, Kaplan isn’t interested in that part of the story, and he instead focuses on the “baneful drugs.” Weirdly, he says that these drugs are mentioned only in the “earliest versions” of Homer’s texts, which makes no sense since the line clearly appears in the standard Homeric texts.
He suggests that Circe used jimsonweed, a hallucinogenic plant long used to relieve asthma and to induce visions. It is fatal in high doses, but according to Kaplan, while under its influence the men might have had visions that could lead them to be convinced they were animals.
That’s a lot of “ifs,” and besides, unbeknownst to our author, the claim goes back a long way, though with a different plant. As far back as the Renaissance, rationalizing scholars attributed Circe’s magic to a plant, Circaea lutetiana, known as “Enchanter’s Nightshade” and scientifically named in her honor.
One of the biggest challenges is proving that jimsonweed (Datura stramonium), also called the thorn-apple, was present in the Mediterranean basin at the necessary time, not to mention what that necessary time was. There is the question of where exactly jimsonweed originated. About half the sources I was able to find say it is native to Mexico and then spread to Europe after Columbus. The other half claim it is indigenous to India and spread to Europe sometime around the Roman era or later, with a few arguing for an earlier diffusion. Part of this seems to be confusion over similar species of Datura prior to the twentieth century, but there is apparently no clear consensus on where the genus Datura originated or how exactly it spread around the world. Something answering to the name of the thorn-apple was known to the Persians, who secondary sources say used it to induce visions, though so far as I can tell, this was actually Datura metel, described in medieval Persian sources.
So to settle this, I turned to Kaplan’s book, where he confirms that he is referring to Datura stramonium, the North American species, which he says was widespread in the Classical world:
We think she was using Datura and not some other poison for two reasons. First, jimsonweed is found all over the classical world. Second, The Odyssey makes it clear that Circe expects the crew to forget their fatherland. More specifically, she is expecting an amnesia-like effect on par with what Datura actually causes.
Now, it isn’t impossible that the plant was found in the Mediterranean, or at least one of the Datura species, but it seems that the Greeks weren’t aware of it until after they started having commerce with India, many centuries after Homer.
Incidentally, the claim that Circe used Datura stramonium isn’t original to Kaplan, despite his use of first-person pronouns. I’ve found it in books going back to the 1990s, and they in turn say that it goes back to at least 1983, when it appeared in A. Plaitakis and R. C. Duvoisin, “Homer’s Moly Identified as Galanthus nivalis L.: Physiologic Antidote to Stramonium Poisoning,” Clinical Neuropharmacology 6, no. 1 (1983): 1–5. However, I have not read this article to know their reasoning or evidence; secondary sources say that they raise it as a possibility to justify identifying the white-flowered Homeric plant moly as the snowdrop, an antidote for Datura. They apparently derive this conclusion entirely from treating the Homeric description as a list of “symptoms” to compare to various poisons. In other words, they assumed that the story was true in order to prove it had a basis in fact.
None of this should detract from the fact that the ancient Greeks, and the Mycenaeans before them, were highly skilled in the use of plants, both for medicine and for magic. As I discussed in my book Jason and the Argonauts through the Ages, there is a strong argument many scholars have made that the medicinal skills attributed to Medea were originally the possession of Jason before the Greeks decided that “magic” was an affront to the gods and devolved it onto witches. Certainly, the passage in Homer is meant to reflect what the Archaic Greeks imagined plant-based magic could do, but that isn’t the same thing as tracing a specific magical action to the chemical processes of a specific plant, much less, as Kaplan does, outlining which neurotransmitters were involved in the hallucination.
It’s funny that those who investigate myth always find in it a reflection of their own beliefs: Folklorists find in them storytelling, historians distortions of real events, and scientists misunderstood science.
Kaplan, for his part, plays the role of Euhemerus and imagines that there were real events that undergird the Homeric fantasy:
Does this mean that Odysseus and Circe were real? In the literal sense, I doubt it. However, a talented female poisoner might have been living on an island who used her knowledge to lead natives to worship her as a demigod. At some point in history someone might also have learned that consuming snowdrop provided protection against certain diseases and poisons. A local hero might have known a thing or two about herbalism, stood up to a cruel poison-wielding witch, proved that he was resistant to her magic, and come to be known as the great-grandson of Hermes . . . and wouldn’t that be cool?