New methods are proposed for the measurement of the number of extracellular neutrophil traps in peripheral blood and mucosal secretion. Effect of microbial factors on the ability ofgranulocytes to release nuclear DNA into extracellular space and form extracellular traps is evaluated. Normal microflora species are shown to more actively stimulate build-up of extracellular network. Formation of extracellular neutrophil traps may be a major efficacious mechanism for mucosal antimicrobial protection.