This review considers data regarding fundamental and applied investigations in human microbial ecology received over the last 15 years. Analysis of these data enabled the author to come to the conclusion that in natural habitats there are practically no metabolic processes or physiological functions of a living being that would not need a direct or indirect participation of symbiotic microbiota. The condition of the host microbial ecology should be considered one of the main biogenic factors that determine human health and disease. The author substantiates the necessity to create an international interdisciplinary programme 'Human microbial ecology: scientific and applied aspects', drawing widely on Russian scientists and other specialists for its realization. Some priority scientific and applied directions in the traditional, biochemical, molecular, evolutional, clinical microbial ecology, microecological toxicology as well biothechnological aspects of host microbial ecology are suggested. Their realization by an international association of scientists, clinicians and biotechnologists will allow accelerated working out and introduction of principally new microecological approaches for prophylaxis and treatment of many widely distributed diseases, as well utilization of the biotechnological potential of human normal microflora representatives in the microbial industry.