Pan SY, Zhou SF, Gao SH, Yu ZL, Zhang SF, Tang MK, Sun JN, Ma ML, Han YF, Fong WF, Ko KM,
 School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China.
 College of Pharmacy,University of South Florida, Tampa, USA.
 School of Basic Medicine, Beijing University of Chinese Medicine, Beijing, China.
 School of Chinese Medicine, Hong Kong Baptist University, Hong Kong.
 Department of Chemistry, Hong Kong Baptist University, Hong Kong.
 Department of Applied Biology & Chemical Technology, Hong Kong Polytechnic University, Hong Kong.
 Division of Life Science, Hong Kong University of Science and Technology, Clear water bay, Hong Kong.
With tens of thousands of plant species on earth, we are endowed with an enormous wealth of medicinal remedies from Mother Nature. Natural products and their derivatives represent more than 50% of all the drugs in modern therapeutics. Because of the low success rate and huge capital investment need, the research and development of conventional drugs are very costly and difficult. Over the past few decades, researchers have focused on drug discovery from herbal medicines or botanical sources, an important group of complementary and alternative medicine (CAM) therapy. With a long history of herbal usage for the clinical management of a variety of diseases in indigenous cultures, the success rate of developing a new drug from herbal medicinal preparations should, in theory, be higher than that from chemical synthesis. While the endeavor for drug discovery from herbal medicines is "experience driven," the search for a therapeutically useful synthetic drug, like "looking for a needle in a haystack," is a daunting task. In this paper, we first illustrated various approaches of drug discovery from herbal medicines. Typical examples of successful drug discovery from botanical sources were given. In addition, problems in drug discovery from herbal medicines were described and possible solutions were proposed. The prospect of drug discovery from herbal medicines in the postgenomic era was made with the provision of future directions in this area of drug development.