According to historical accounts described in The Essiac Report, Rene Caisse and Dr. Charles Brusch worked together in Cambridge, Massachusetts, from 1959 to 1967 during a period in which Essiac and variations of the formula were investigated. The original Essiac formula contained 4 herbs, but historical records describe additional herbs—sometimes referred to as “potentiators”—being explored alongside the four-herb formula as part of this work. Rene Caisse and Dr. Charles Brusch chose the 8 herb formula as the one that outperformed all others.
