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, especially for minor ailments, and modern scientific medicine still depends on plants, and the knowledge gained from plants, for some essential drugs. With this widespread use has come the assumption that plants identified as having medicinal properties 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 destruction of plant-rich habitats such as the tropical forests, there can be no guarantee that we will continue to benefit indefinitely from this valuable resource provided by medicinal plants.

Today, many medicinal plant species face extinction or severe genetic loss but detailed information is lacking. For most of the endangered species no conservation action has been taken, and for most countries there is not even a complete inventory of medicinal plants. Much of the knowledge on their use is held by traditional societies, whose very existence is now under threat.

In the light of this situation, the World Health Organization, IUCN - The World Conservation Union, and the World Wide Fund for Nature convened an International Consultation on the conservation of medicinal plants, held in Chiang Mai, Thailand in March 1988 and hosted by the Ministry of Public Health of the Royal Thai Government. The Consultation brought together for the first time in the same forum policy-makers and scientists from the two key areas of health care and nature conservation. This book is the outcome of that meeting, detailing in a series of papers by leading experts the problems 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.