The claim that drug use was pervasive in classical antiquity and shaped Western civilization's founding texts.
Documented
The raw materials are not in dispute
The kykeon, the barley drink consumed at the Eleusinian Mysteries, is documented in the Homeric Hymn and was the subject of Wasson, Hofmann, and Ruck's The Road to Eleusis, which proposed an ergot base. Opium and mandrake appear throughout Roman medical literature. Dioscorides catalogued hundreds of drug plants. Ammon Hillman's dissertation on pharmacy in Roman literature was accepted at Wisconsin, and The Chemical Muse (2008) assembled the ancient testimonies at length.
Assessment: The pharmacopeia is documented ancient fact. What Hillman built on it is where the record splits: the Bryn Mawr Classical Review found assertion piled on assertion, and his sweeping causal claims, democracy as a drug effect, remain his alone.
Stories
The oracle was high
The story everyone knows: the Pythia at Delphi sat over a chasm breathing vapors, and the god spoke through the intoxication. Plutarch describes her altered state. The geological hunt for the gas, ethylene, ethane, CO2, has run for a century.
Assessment: The ancient testimony is documented; the gas is contested. A 2001 Geology paper claimed ethylene traces; later surveys found the springs produce nothing psychoactive. The story survives because it explains prophecy chemically, and neither side can close the case.
Interesting claims
Civilization was a controlled substance
Hillman's strong form: mystery cults were drug rituals, philosophical ecstasy was pharmacological, and the classical tradition is the record of an enforced forgetting, a civilization that got high, founded everything, and let later ages pretend otherwise. His followers extend it to the Eucharist and early Christian anointing oils.
Assessment: The strongest version proves too much. Ergot at Eleusis is a serious hypothesis; ergot as the engine of democracy is not. The pattern matches the whole shelf: a documented anomaly inflated into a total theory. The forgetting, though, is real: the drugs are in the texts, and the textbooks preferred not to translate them loudly.
Sources and further reading
D.C.A. Hillman, The Chemical Muse, Thomas Dunne, 2008
Homer, Odyssey 4.219-234, nepenthe
Worth asking
If the oracle inhaled fumes, the mystai drank spiked barley, and Roman poets praised the poppy, where exactly does 'natural' religion begin?