Above is a photo of the Catholic sacrament of the Eucharist.
It is a cracker made in a factory and contains thirteen calories, two grams of carbohydrates, and a quarter of a gram of protein.
Per the doctrine of "transubstantiation," when served at Mass the "essence" of the otherwise ordinary cracker transforms, quite literally, into the body of Christ.
"Transubstantiated" or otherwise, it possesses no known curative or psychological effects.
Below is a photo of psilocybe mexicana, a holy sacrament among certain peoples of Central and North America:
Like the cracker in Roman Catholicism, psilocybe mexicana is considered the "flesh of God" within some traditions.
Unlike the physiologically and psychologically inert cracker, however, the mushroom "entheogenic" (meaning, "to generate god within"). Psilocybe mexicana contains psilocybin, a psychedelic compound which can reliably occasion mystical experience.
Such psychedelic-induced peak spiritual experiences can improve well-being over the long term; foster a keener appreciation for beauty and heighten intellectual curiosity, and generally imbue one with a greater sense of awe—which, in turn, can increase altruism, prosocial behavior, and ethical decision-making. Psychedelic-assisted psychotherapy can mend and deepen relationships and cure PTSD, depression, and addiction, among other woes and disorders.
And, to boot, psychedelics can demonstrably and significantly increase creativity.
The use of psilocybe mexicana by indigenous Central and North Americans is but one of many examples of the sacramental use of entheogens. Such practices date back at least 10,000 years, include a wide variety of substances, and span virtually every culture—including the cradle of Western civilization.
Ingestion of the psychedelic brew kykeon was an integral part of the Eleusinian Mysteries in ancient Greece. The Eleusinian Mystery tradition spanned nearly 2,000 years, from approximately 1500 BC into the 4th-century. "The ultimate design of the Mysteries," wrote Plato, "was to lead us back to the principles from which we descended… a perfect enjoyment of intellectual [spiritual] good." 
Cicero, Roman statesman and philosopher, spoke thusly of the psychedelic initiation rite:
For among the many excellent and indeed divine institutions which your Athens has brought forth and contributed to human life, none, in my opinion, is better than those mysteries. For by their means we have been brought out of our barbarous and savage mode of life and educated and refined to a state of civilization; and as the rites are called "initiations," so in very truth we have learned from them the beginnings of life, and have gained the power not only to live happily, but also to die with a better hope. 
The Mysteries ended by decree by Christian Roman emperor Theodosius I in 392 AD, and the sacred sites were destroyed a few years later by Arian Christians. Over the next millennia, Catholic missionaries attempted to suppress the use of entheogens across the globe.
While the Church was partly successful in doing so, various sects—often openly in the non-Western world and typically covertly in the West—nevertheless continue to make sacramental use of these most powerful agents of healing and spirituality.
Meanwhile, Catholicism and broader Christendom continue to make sacramental use of crackers.
- Taylor, Thomas, The Eleusinian and Bacchic Mysteries: a Dissertation, (1790), p. 49.
- Cicero, Laws II, xiv, p. 36.
I am lawyer and writer with a forthcoming book tentatively entitled, "Psychedelic Revolution: Living Better with Psychedelic Drugs and Why Prohibition is Unconstitutional." See here for a transcript of a talk I recently gave outlining parts of the major theses of this book.