The biomedical model of health and disease dominates in current medical practice. The model attributes key role to biological determinants and explains disease as a condition caused by external pathogens or disorders in the functions of organs and body systems. Such an approach has its historic justification and has proved effective in the control of massive infectious diseases. However, now that chronic non-infectious diseases prevail, its efficacy has not only become questionable, but also the issue has been raised of its economic justification. The extension of biomedical approach and attribution of equal importance to psychosocial factors have become an imperative in the improvement of treatment efficacy and disease control, together with humanisation of relations between health staff and patients. A new biopsychosocial model has been suggested, that takes into account all relevant determinants of health and disease and that supports the integration of biological, psychological and social factors in the assessment, prevention and treatment of diseases. It does not diminish the significance of biological factors, but extends a rather narrow approach. The biopsychosocial model served as incentive for many studies of how psychological and social factors influence the development, course and outcome of a disease, giving rise to the development of interdisciplinary field--particularly the fields of health psychology and psychoneuroimmunology. Their contribution to better understanding of the impact of psychosocial factors on health stimulates greater interest of medical theory and practice in more holistic approach to a patient. However, the changes of the old, organ oriented approach are still too slow and too narrow.