From the ethnographic, scriptural and mythographic records and the observations of naturalists it appears likely that: · The psychoactive properties of various plants were discovered anciently by human observation of the effects of plant drugs on animal behaviour. · The psychoactive properties of plants were sometimes also discovered through the consumption milk or flesh of animals that had foraged on psychoactive plants. · The first two points may be a partial explanation for the motif of the Tree of Life flanked by goats or deer and explain the prominence of goats in the rituals of various religious groups employing psychoactive plants. · Ritual omphagia may have been established through the eating of the raw flesh of animals that had grazed on, or had been fed, psychoactive plants. This ritual may have been established because the plant was otherwise unpalatable, because this route mitigated its toxicity, or because the plant’s psychoactivity was originally discovered in this way. In addition, it might be necessary to consume the flesh raw to preserve or maximise its psychoactive potency. · Priests (covertly?) dosed animals with psychoactive plants prior to using their milk or flesh in sacrificial rituals as well as mixing psychoactive substances with meat or milk, before dispensing them to the congregation. Chrysame, the priestess of Enodia, and the prophet Melampus both certainly knew this trick.