Nearly all cultures, from ancient times to today, have used plants as a source of medicine. In many developing countries, traditional medicine is still the mainstay of health care and most of the drugs and cures used come from plants. In developed countries many people are turning to herbal remedies. With this widespread use has come the assumption that plants identified as having medicinal qualities will be available on a continuing basis. However no concerted effort has been made to ensure this and in the face of the threats of increasing demand, a vastly increasing human population and extensive forest destruction, there can be no guarantee that we will continue to benefit indefinitely from this valuable resource. In light of this situation the World Health Organisation held a meeting in 1988. This book is the outcome of that meeting, detailing in a series of papers by leading experts the problems of which need to be addressed, the existing experiences from a range of countries and the future direction which must be taken to ensure the conservation of the world's medicinal plants.