Ergot is a fungus that infects rye and related grains. It produces alkaloids that cause ergotism — convulsions, vasoconstriction severe enough to cause gangrene, hallucinations, death. Medieval Europeans called it St. Anthony's Fire. The fungus is one of the most dangerous contaminants in the food supply, and its effects are well documented across centuries.
Ergot also produces d-lysergic acid amide (LSA) and its isomer iso-LSA — psychoactive compounds structurally related to LSD. Albert Hofmann first synthesized LSD from ergot alkaloids in 1938. The psychoactive and the toxic compounds coexist in the same fungus.
Antonopoulos, Dadiotis, Ioannidis et al. (Scientific Reports, 2026) tested whether ancient Greek priestesses of the Eleusinian Mysteries could have separated the two. They boiled ergot in lye — sodium hydroxide at pH 12.5, a solution achievable with wood ash — for two hours. The toxic ergot alkaloids degraded. The psychoactive ones survived. Each gram of processed ergot yielded approximately 0.54 mg of LSA and 0.48 mg of iso-LSA, within the range to induce altered states of consciousness.
The processing window is narrow. Below pH 12, the toxic alkaloids survive. Above pH 13 (or with longer boiling), the psychoactive compounds degrade too. The two-hour mark at pH 12.5 sits in a zone where the toxic compounds are destroyed faster than the psychoactive ones — a kinetic differential, not a chemical separation. Both classes of alkaloid are susceptible to alkaline hydrolysis. The toxic ones break down first because their molecular structure is more vulnerable to the conditions. The process exploits a difference in degradation rates, not a difference in kind.
The Eleusinian Mysteries ran for nearly two thousand years — from approximately 1500 BCE to 392 CE, when Theodosius I closed the sanctuaries. The kykeon, the ceremonial drink, was central to the initiation. Its recipe was a closely guarded secret. The ingredients recorded in ancient texts — barley, water, mint — are inert. If the psychoactive component was processed ergot, the secret was not the ingredients but the processing parameters: the pH, the temperature, the duration. Knowledge of what to add was insufficient. Knowledge of how to transform it was everything.
The structural observation: the difference between poison and sacrament is not the substance but the processing trajectory through it. Ergot contains both outcomes simultaneously. Which one you get depends on the path — and the path has narrow tolerances that require empirical knowledge passed down through generations. The priestesses were not pharmacologists in any modern sense. They were custodians of a procedure whose parameters they could not have articulated in chemical terms but which they maintained with enough precision, over two millennia, to reliably navigate between death and vision.