Chao Yuanfang lived in a period from the end of the Sui Dynasty (581-618) to the beginning of the Tang Dynasty (618-907). His native place and dates of birth and death are unknown. Legend has it that he was from Xihua. Chao Yuanfang was most active during the Daye reign (605-615) of the Sui Dynasty, when he worked as an imperial physician, and made many brilliant achievements. However, in the bookHistory of the Sui Dynasty, there is no record of Doctor Chao. Only in the novelThe Story of the Great Canal Erais there a paragraph of record of him. It is said that in the August of the fifth year of Daye reign, the general superintendent of the Great Canal project got a disease called "Fengni Zheng" (something like rheumatism), and Emperor Yang ordered the minister of imperial medical affairs, Chao Yuanfang, to treat the superintendent.

Although Chao Yuanfang's life story is little known to us due to lack of historical record, yet his great contribution to the 5,000-year civilization of the Chinese nation will be ever remembered in the annals of history owing to the monumental work of etiology of traditional Chinese medicine,Zhu Bing Yuan Hou Lun(Treatise on Causes and Symptoms of Diseases), compiled under his leadership.

The Sui Dynasty established the earliest "Ministry of Imperial Physicians" in Chinese history for medical education, which was also the earliest recorded large-scale official institution of medical education in the world. The royal court also organized scholars to extensively collect data of traditional Chinese medicine, chiefly being the prescriptions and proved recipes of all dynasties. The huge 2,600-volume book of recipes,Sihai Leiju Fang(Collection of Recipes of the Whole Country) was compiled and finished in this period. It was in this background that the first monograph on pathogenic symptomatology in China,Treatise on Causes and Symptoms of Diseases, compiled in the charge of Chao Yuanfang at the royal order, came into being. It is the first masterpiece in the history of Chinese medicine development and expounds the pathogenic factors, symptoms and classification of diseases systematically, scientifically and thoroughly.

Treatise on Causes and Symptoms of Diseaseswas also calledChaoshi Bingyuan(Causes of Diseases by Doctor Chao), which represents the great contribution done by Chao Yuanfang's contribution to the publication of the great work. The whole book is in 50 volumes; the causes and symptoms of diseases are classified into 67 kinds, and there are altogether 1,720 entries of monographic writing in the book. Every entry of monograph writing includes the pathogenic factors of the disease, its pathology, and its symptoms. After each entry, there are some ways of treatment attached, but there is no list of recipes as in books of recipes of all times, to show that the masterpiece is meant specially for probing into the "causes" and "symptoms" of all kinds of diseases. The publication ofTreatise on Causes and Symptoms of Diseasesmarked the systematic establishment of the theory of etiology and symptom science of traditional Chinese medicine. As someone commented, it "gathers all excellent theories, carries out in-depth study, and discusses all kinds of diagnosis and treatment, serving as a medical encyclopedia". Many of the famous works of Chinese medicine take this book as their theoretical basis in their discussion and analyses on causes and symptoms of diseases, such asQian Jin Yao Fang(Essential Prescriptions Worth a Thousand Pieces of Gold) andQian Jin Yi Fang(Additions to the Prescriptions Worth a Thousand Pieces of Gold) by Sun Simiao of the Tang Dynasty (618-907),Wai Tai Mi Yao(Secret Ways of Treatment) compiled by Wang Tao of the Tang Dynasty, the great book of prescriptions of the Song Dynasty (960-1279),Taiping Hui Fang(Best Recipes of Taiping), and so on.