Antibacterial activity of neutrophils and peritoneal macrophages toward massive doses of Staphylococcus aureus is studied in vivo. Two types of antibacterial response are revealed: non-phlogogenic (physiological) and phlogogenic (inflammatory). Nonphlogogenic reaction is characterized by pronounced antibacterial effect of phagocytes on cocci. Transition to phlogogenic response is accompanied by impaired function of phagocytes involving their self-destruction and disintegration, which decreases their antibacterial activity and promotes inflammation. ©1998 Plenum Publishing Corporation.