Treatment and prevention
Today, doctors can cure bubonic and sometimes pneumonic cases of plague by giving antibiotics as soon as they suspect plague. Delay can be fatal. Cases of septicemic plague are fatal even today, as this swift infection usually kills before plague can be diagnosed. Unaware of bacteria and lacking antibiotics, medieval doctors had no useful weapons against plague. The approach of bland diet, bloodletting, and purging (with laxatives or enemas) was standard treatment for most fevers. Lancing the buboes probably served only to splatter bystanders with infectious fluids.
Nor did people of the 1300's have any effective means of preventing plague. Quarantine, which might have stopped a disease transmitted person-to-person, was useless against an infection carried by rats that could run freely. People who fled, believing themselves healthy, often carried the disease to their new homes. Prayer and rituals proved ineffective; some people, seeing that priests and nuns were not immune, turned instead to wild living, drinking, and gambling.
In many towns, people attacked Jews and other outsiders, such as foreigners and lepers, under the assumption that these people had somehow caused the epidemic. Religious leaders actually discouraged these persecutions, believing the plague to be the work of God, not humans, and noting that Jews were infected as often as Christians. Still, despite orders from the pope and many rulers, mobs eliminated more than 200 Jewish communities in France, Spain, Switzerland, Germany, and elsewhere.
Based on "Apocalypse Then: A History of Plague." The 1992 World Book Health & Medical Annual, pp. 166-181