RESUMEN
The relevant provisions of bloodletting for expelling pathogens are collected from the works of the medical representative scholars in Jin-Yuan Dynasties and Ming-Qing Dynasties respectively to construct the databases of bloodletting for expelling pathogens of Jin-Yuan Dynasties and Ming-Qing Dynasties. Using frequency analysis, the bloodletting device, bloodletting location, bloodletting volume, the related pathogens and indications are compared between these two times so that the evidences could be provided for the inheritance and development of the academic thought of bloodletting for expelling pathogens. It is found that the three-edge needle is the most commonly used device for bloodletting in Jin-Yuan Dynasties and Ming-Qing Dynasties and