Determination of morpho-physiological changes in cells of a lactobacillus industry strain suppressed by antagonistically active clinical cultures of Staphylococcus aureus. 5 clinical strains of Staphylococcus aureus detected among 42 strains isolated previously in atopic dermatitis were used. Bacteria of the industry strain Lactobacillus plantarum 8PA-3 that synthesize bacteriocin-like inhibitory substances (BLIS) were used as target-cells. Suppression of growth of lactobacilli cells by staphylococci was performed on modified agar nutrient medium MRS by delayed antagonism method. Ultrastructure changes in lactobacilli cells exposed to staphylococci BLIS were studied by various methods of transmission electron microscopy. Destructive changes (exfoliation of small layered fragments of peptidoglycan layers) were detected in the cell walls of lactobacilli suppressed by staphylococci BLIS, and rearrangement of ultrathin structure of their cytoplasm with the destruction of protein-ribosomal complex was noticed. CONCLUSION; Clinical S. aureus strains that produce BLIS, suppress antagonistic activity of lactobacilli were revealed, and morpho-physiological changes in lactobacilli target-cells damaged by BLIS were detected. Local damage of cell components manifested by the destruction of cytoplasm and formation of "cell shadows".