The Kephisos River marked the boundary between Athens and Eleusis, and as soon as it was crossed the rituals leading up to initiation into the Eleusinian Mysteries began.
The most important of these was the drinking of kykeon, after which the initiates began to chant. Demeter could not drink the wine offered to her in the Eleusinian myth, since Dionysus had connived in the kidnapping of Kore, so she invented kykeon.
Various theories have evolved that kykeon was made with ergot-diseased grain, whose mild dose of LSD would still be hallucinogenic, but the basic recipe that has come down to us suggests that enough ingredients with mind-altering properties were in play not to needed a dose of ergot.
Kykeon was made with barley, water and fresh mint, which fermented quickly and turned into an alcohol that must have had a particularly powerful effect on those used to drinking at most diluted wine (drinking wine neat was a sign of ‘Barbarians’). In addition, depending on the variety used, the oil of the fresh mint could be either a stimulant or a soporific. The initiates drank a gulp, rather than sipped, from the metal jars they carried on their heads.
The unique shape of the kykeon jar was represented on Athenian coins, another indication of the importance of the Eleusinian cult to the state. Here it can be seen on a Roman frieze that once decorated the exterior of the City Eleusinion in Athens.
Pausanias (1.37.4) also notes a temple to the God of Broad Beans on the sacred way to Eleusis, just after the Kephisos River, and hints at their role in the Eleusinian rites themselves by categorically refusing to discuss them.
In the Arcadian variant of the tale, Demeter gave them all the fruits of the soil except for broad beans. This one pulse that she withheld can be explained by its use in a variety of mystery cults.
Raw broad beans are rich in a form of dopamine (levodopa) – some varieties can be fatal if eaten in excess – and so were only prepared as part of select religious ceremonies. Modern medicine has also shown that many Mediterranean peoples suffer from a hereditary deficiency of the enzyme G6PD (Glucose-6-phosphate dehydrogenase); this deficiency protects them from the full effects of malaria, but makes them more susceptible to the mind-altering properties of beans.
In order to prevent people eating broad beans at home, a variety of holy laws were created, with associated ‘explanations’ for why they were taboo, and so eating them made into a criminal offence. This taboo has permeated to this day in Greek cuisine - Israeli falafels contain broad beans, Greek ones only chick peas.
When dopamine, alcohol and mint were combined in this way on an empty stomach, LSD would have been superfluous. Although poppies were also associated with Demeter and Kore, this was probably linked to pain and death, rather than the use of opium at Eleusis.