Jing Xiao Chan Bao(Treasured Knowledge of Obstetrics), also calledChan Bao, was compiled between 847 and 852.

The book is the earliest monographic work on obstetrics available inChina. The author collected obstetrics theories of many scientists before the Tang Dynasty (618-907), and compiledt many folk recipes and his personal clinical experiences in the book.

Chan Baois in 3 volumes, containing 52 chapters and 371 prescriptions. The first volume expounds fetus nourishing, fetus protection, miscarriage prevention, food prohibited, hyperemesis gravidarum, threatened abortion, hemorrhage, abdominal distention, and many other symptoms of dystocia. It especially gives a detailed introduction to cross birth and footling presentation. The second and third volumes contain 25 chapters altogether, discussing the treatment of all kinds of obstetrical diseases, with some prescriptions attached.

The book offers a detailed discussion on symptoms of gestation, parturition, and post partum. For each type of disease, theoretic discussion comes first, and then come the prescriptions; In therapy, stress is put on conditioning of "qi"(vital energy) and blood,and invigoration of spleen and kidney. It introduces a simple and straightforward way for emergency treatment of swooning off due to excessive loss of blood during delivery.

The book preserved the experience and prescriptions in obstetrical treatment before the Tang Dynasty (618-907), set the rules in obstetrics and gynecology for later generations, and contributed a great deal to the development of this branch of science inChina.