Introduction

The value of biodiversity as a source of pharmaceutically active substances has been the subject of a number of studies, for example Pearce and Puroshothaman (this volume), McNeely (1988), Farnsworth and Soejarto (1985) and Principe (1991). This value is now being cited as one of the many arguments for conserving natural habitats and, in particular, tropical forests which contain the largest number of plant species. These analyses, however, ignore the additional role of these as sources of medicines in the form of herbal treatments used by the majority of people in developing countries. Furthermore, this direct local use of plant resources contributes to the preservation of species and habitats, and can be used as the basis for conservation policies centred on indigenous management regimes and utilisation. The success of such policies depends on the allocation of property rights and the cultural status of herbal medicine which could be an important component of primary health care in developing countries, as advocated by the World Health Organization.

Recent attempts to value non-timber forest products and in particular medicinal plants (Balick and Mendelsohn, 1992) have examined only the current local market value of these products and have not attempted any in-depth evaluation of the benefits to rural communities of traditional health strategies.