According to Allegro, the mushroom's psychoactive properties, which include euphoria, visions, and a sense of unity with the divine, were seen as a means of achieving spiritual enlightenment and communion with God. He suggests that the Last Supper, a pivotal event in Christian tradition, was actually a ritualistic ceremony involving the consumption of the sacred mushroom.

To understand Allegro's theory, it is essential to consider the historical context in which he wrote. The 1960s and 1970s saw a surge of interest in psychedelics and their potential role in shaping human culture and spirituality. The discovery of the psychoactive properties of various plants and fungi, including the Amanita muscaria, sparked a new wave of research and speculation about their use in ancient rituals and ceremonies.

One of the most compelling pieces of evidence presented by Allegro is the association of the Amanita muscaria with the redemptive and regenerative themes in ancient mythology. He notes that the mushroom's distinctive red cap and white spots resemble the iconography of the sacred king and the crucified god, which are common motifs in ancient mythology.