Xin xiu ben cao (Newly Revised Materia Medica), also called Tang ben cao (Materia Medica of the Tang Dynasty) is the first state pharmacopoeia in the world, the original edition of which was lost yet cited by various books. After analyzing the TE in Jia You ben cao (Materia Medica of Jia You Reign) supplemantarily cited by Zhang Yuxi in the Song Dynasty, the author holds that Zhang himself didn't witness Xin xiu ben cao (Newly Revised Materia Medica) and the so-called TE ought to be derived from Shu ben cao (Materia Medica of Sichuan) because both share the same features. Inference can also be drawn that Xin xiu ben cao ( Newly Revised Materia Medica) might have been lost at the time when Jia You ben cao (Materia Medica of Jia You Reign) was compiled in the 2 nd year of Jia You Reign (A.D.1057). As the TE was not directly extracted from Xin xiu ben cao (Newly Revised Materia Medica), the trustworthiness of the texts allegedly cited from Xin xiu ben cao should be evaluated in many ways and it should be dealt with prudently while recompiling Xin xiu ben cao (Newly Revised Materia Medica).