excrement In Alchemy, a Symbol of the nigredo, the stage of putrefaction that begins the Great Work. Human and animal excrement were employed in various alchemical procedures aimed at creating the Philosopher’s Stone. Excrement also symbolizes the darkness of the unconscious from which enlightenment arises. It is the power of a person, the essence of one’s being. It associated with gold and riches and is the fertilizer of new growth and beginnings. See also urine.