Formerly used as a treatment to reduce excess blood (one of the four humors of medieval medicine).
2.
Indiscriminate slaughter. Synonyms:battue, bloodbath, bloodshed."Ten days after the bloodletting Hitler gave the action its name" , "The valley is no stranger to bloodshed and murder" , "A huge prison battue was ordered"
... the doctor, searching in his bag for his bloodletting instruments. Then he approached the bed, and laid his fingers on ... — The Nameless Castle • Maurus Jokai
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