Natural products are the most successful source of drugs. Of the 877 small-molecule new chemical entities introduced between 1981 and 2002, roughly half were natural products, semi-synthetic natural product analogues or natural mimics. Chinese herbs (traditional Chinese medicines, TCMs) have been used for prevention and treatment of diseases for thousands years. It has been attracting intensive attention in the trends of back to nature. As herbal medicines, the conditions of growth, harvest time, process and storage etc. will undoubtedly affect the presence and concentration of the bioactive constituents, thus affecting their quality and efficacy. Up to date, there are few books focussing on the relationship, which is the bridge between TCM and modern medical science, of traditional clinic uses, pharmacological activities and quality control of Chinese herbs. Unfortunately, bioactive compounds in Chinese herbs are usually not or only partially known. Actually, the active compounds considered in Chinese herbs may be different according to their clinical indication. In addition, it is considered that the curative effect of Chinese herbs is an integrative result of a number of bioactive compounds. Therefore, how to control the quality is a big problem. We would like to discuss the quality control based on their traditional clinical uses and pharmacological activities in this book, which is the fundamental step towards developing and modernising such products into evidence based medicines. It will also help the peoples to understand TCMs in modern scientific angles. This book is designed primarily as a textbook for or adjunct to course in herbal remedies, food safety or quality control of herbs. It is also a professional reference whom is in the area of drug discovery, pharmaceutical analysis and food chemistry.