Purges
Around the same time as bloodletting was being explored, physicians began to think that the cause of mental illness lay within a patient’s body, and could be cured by expunging it through pretty disgusting means.
One of the most common treatments was to induce vomiting. Ancient Greeks used black hellebore, a foul-tasting though beautiful flower. Bitter apple was also used for its bad taste, and Americans used tobacco. The Arabs made a concoction of myrobalans (an astringent plant), rhubarb, and senna, which has laxative properties, to clear the bowels.
Apparently these purges were meant to clear people of melancholy, however, the process itself would seem to induce a melancholic state, rather than cure one. Indeed, since the process had the same rationale as bleeding, purging in any fashion is just as ineffective as bleeding — and just as unpleasant.
If you enjoyed this look at how humanity used to “cure’ mental illness, check out our posts on the worst execution and torture methods throughout history.