This book is abbreviated as Shiyi, also known as Chen Cang-qi materia medica. It was written by Chen Cang-qi in the 27th year of the Kaiyuan era of the Tang Dynasty (739).

This book is a materia medica work, consisting of 1 volume of preface and examples, 6 volumes of supplements, and 3 volumes of explanations. Since the book mainly focuses on supplementing the drugs omitted in the Tang Dynasty's Xinxiu Bencao for fistula disease, it is named "Shiyi" (Supplements). The book is now lost, but it has been cited in various medical texts. The Japanese Ishinpo, the Song Dynasty's Zhenglei Bencao, and the Ming Dynasty's Bencao Gangmu have extensively quoted from it. Its main content is preserved in Zhenglei materia medica. The collated edition by Shang Zhongjun, Bencao Shiyi, was circulated in mimeographed form by the Scientific Research Department of Wannan Medical College in 1983 and is collected in various places.

The book is divided into three parts. The preface and examples section serves as an introduction, recording the content of "ten kinds of formula." It states that drugs have ten kinds of formula: dispersing, unblocking, tonifying, purging, light, heavy, astringent, slippery, drying, and moistening. The supplements section includes 692 drugs, categorized into sections such as minerals, herbs, trees, animals and birds, fruits, vegetables, and grains. Each drug entry includes the drug name, nature and flavor, toxicity, efficacy, indications, origin, morphology, and preparation methods. Bencao Shiyi was an important materia medica work in the Tang Dynasty, second only to Xinxiu Bencao.