Written by Zhang Song, a physician in the Southern Song Dynasty, Jiu yuan fang (Formulary of Exploring Cause) was a lost clinical experienced formulary book. Totally 124 items of its original texts were quoted and remained in some other ancient Chinese medical books, such as Fu zai wan an fang (Formulary for Absolute Safety), Bao qing ben cao zhe zhong (Compromised Materia Medica of Baoqing Reign), Bencaogangmu (Compendium of Materia Medica) and Puji Fang (Prescriptions for Universal Relief) etc. After compiling and editing these scattered records, it was found that Jiu yuan fang was the earliest book carrying the Yupingfeng Powder, with rather high value of literature research and significance of clinical application.
Books History, Medieval