Gamboge (Garcinia gum-resin purgative)
Gamboge is a gum-resin obtained from Garcinia trees, used historically in pharmacy as a drastic purgative and as a yellow pigment. The Dictionary of National Biography names it as a principal ingredient of Morison’s Vegetable Universal Medicine, the pill James Morison sold from 1825 through the British College of Health. Morison concealed the full recipe, which was not made public until the early twentieth century; gamboge is the constituent the biographical record fixes by name. In the Hygeian doctrine the pills worked by purging the supposed impurity of the blood through the bowels, so heavy dosing was marketed as harmless and even desirable. Gamboge has no such action: it is a harsh cathartic that, taken in the large quantities Morison’s agents administered, produced the severe purging implicated in deaths attributed to the pills.