Medical anthropology is concerned with both the causes and consequences of human sickness, and its various theoretical orientations can be grouped into four major approaches: medical ecology, critical medical anthropology, interpretative medical anthropology, and ethnomedicine. While medical anthropologists of all theoretical persuasions have examined why people get sick, the analysis and understanding of patterns of treatment has been largely confined to ethnomedicine. Historically, more emphasis has been placed on the personalistic or supernatural aspects of ethnomedical systems than on naturalistic or empirical components. While this focus has produced valuable insights into the role of ritual and belief in healing, it has led to the impression that traditional medicine is primarily symbolic. Moreover, it ignores the theoretical bases of traditional healing strategies and the practical means by which most of the world heals itself, namely plants. Recently there has been more interest in the empirical character of ethnomedical systems, and in this paper we consider the role that medical ethnobiology has played in this shift of focus. We begin with a brief history of medical anthropology to illuminate why naturalistic medicine was neglected for so long. We then review exemplary research in two areas of medical ethnobiology -ethnophysiology and medical ethnobotany -that address the study of naturalistic aspects of medical systems. We conclude with suggestions for future research at the interface between medical ethnobiology and medical anthropology that will contribute to both fields.Medical anthropology is the study of the causes and consequences of sickness 1 in human beings, and its diverse theoretical orientations can be grouped into four major approaches: the medical ecology/biocultural approach, the political economy/critical medical anthropology approach, the interpretative or postmodern approach, and the ethnomedical approach. Medical ecology encompasses the contributions of biological anthropology to the understanding of human disease. An ecological perspective is employed to analyse the interaction of populations, pathogens, and environments at the core of disease processes (Armelagos, Leatherman, Ryan & Sibley : ; McElroy & Townsend : ). In contrast, critical medical anthropology is concerned primarily with political and economic factors in health and disease (Baer : ; Singer, Valentín, Baer & Jian : -), while interpretative medical anthropology focuses on metaphorical conceptions of the body and shows the social, political, and individual