purgers In Shakespeare's day, the most common treatment for any disease was a purge of one kind or another. It was thought that health was maintained by a balance of the four essential fluids ("humours") of the body—blood, yellow bile, black bile, and phlegm. An excess of a humour was thought to be the fundamental cause of disease, and the cure was a purge of the excess. Yellow bile was purged by inducing vomiting, black bile by the administration of a laxative, phlegm by inducing violent sneezing, and blood by bleeding, either by making an incision or by the application of leeches. The practice of bleeding was so common that a common word for "doctor" was "leech." In all cases, the general idea was to restore the body to health by purging it of the excess which was causing the disease.

Brutus' idea is that he and the rest of the conspirators will be seen as "purgers" who will restore the body politic—the Roman republic—to health.