Book excerpt: This book has been prepared in an effort to address the pressing need for a common language, i.e. international standard terminology and technical terms to be used in traditional medicine. The number of commonly used terms in traditional medicine is estimated to be more than 4000, most of which are included in this book, which is designed for use by students and clinical practitioners and researchers in the Western Pacific Region. This terminology will also be useful to assist Member States in the region in developing evidence-based clinical practice guidelines on traditional medicine.