Psychedelics have a long history of use in religious and spiritual ceremonies. Ancient cultures used natural psychedelics like cannabis, peyote, ayahuasca, and psilocybin (aka magic mushrooms) as medicine to induce an altered state of consciousness and connect with nature. 

Some indigenous people living in the Amazon basin have been using ayahuasca, a blend of the tropical liana Banisteriopsis caapi and other botanical ingredients, as a medicine and to communicate with the spirits of their ancestors. Similarly, some indigenous communities in America use peyote as a religious sacrament, and ancient Greek and Roman civilizations are thought to have used ergot (a fungus that grows on barley, rye, and other grains) in religious ceremonies. 

However, psychedelics in the West became more widespread in the middle of the 20th century. Researchers and intellectuals began using them to explore their effects on the human brain, and the practice eventually became a feature of the counterculture movement of the 1960s. Many "hippies" and others in the counterculture used psychedelics to explore new states of consciousness and probe the mysteries of the psyche.

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