bloodletting vs extermination

bloodletting

noun
  • The archaic practice of treating illness by removing some blood, believed to be tainted, from the stricken person. 

  • The diminishment of any resource with the hope that this will lead to a positive effect. 

  • A circumstance, such as a battle, where a large amount of blood is likely to be spilled through violence. 

extermination

noun
  • The act of exterminating; total destruction or eradication 

  • Elimination. 

How often have the words bloodletting and extermination occurred in a corpus of books? (source: Google Ngram Viewer )