This invention relates to the extraction of psychoactive compounds from organisms for use in medicine. Extraction is carried out with a strong acid or strong base to either promote or inhibit dephosphorylation. The extract in the slurry form is standardized with added excipient so that when it is dried the powdered composition has a specified total psychoactive alkaloid concentration, with a known ratio of phosphorylated to dephosphorylated psychoactive alkaloids.