PURPOSE OF THE REVIEW. This critical review presents an overview of the development in the field of mind-body medicine over the last 10 years and has taken tentative steps toward suggesting the components of a new model of health based on psychoneuroimmunology. While documenting the major shortcomings of present research design, methodology, data analysis, and subsequent hypotheses, this article points out areas of sufficient promise for practical and responsible clinical applications of the research. SEARCH METHOD USED. A thorough review of the clinical and experimental medical literature related to the interaction between mind and body is presented, and the new and complex research in the field of psychoneuroimmunology is analyzed. SUMMARY OF IMPORTANT FINDINGS. Despite the mixed and sometimes conflicting findings in current research, there is an increasingly compelling body of scientific evidence indicating that mind-body interactions are at the root of both health and disease. Research demonstrates that psychological factors seem to play a causal role in the onset and course of many chronic disorders and that psychological, emotional, psychosocial, and behavioral interventions have at least as much proof of effectiveness as many purely medical treatments. MAJOR CONCLUSIONS. There is a substantial growing body of scientific and clinical knowledge which demonstrates an inextricable interaction between mind and body. Such an approach empowers individuals and organizations to assume greater responsibility for health as a basis for the development of a true health care system.