Objective  To apply sterile rat fecal extracts (SRFE) in the establishment of mice septic peritonitis models and evaluate its effect.   Methods  SRFE and/or 5% yeast were added to dilute the broth of different bacteria

0.5 ml of which was injected into each mouse’s peritoneal cavity. Minimal lethal dose (MLD) was compared when there was SRFE or not. Mortality of mice was compared as the change of concentration of SRFE and different ratio (SRFE: 5% yeast).   Results  MLD was decreased 78%~90% with the application of SRFE. Mortality of mice was increased with rise of SRFE concentration. The application of SRFE alone was not so effective and 5% yeast was necessary to cooperate with SRFE. Different ratio of SRFE and 5% yeast didn’t affect the mortality of mice (P0.05).   Conclusion  The application of SRFE can decrease MLD effectively when form mice septic peritonitis models

especially for those bacteria with low pathogenicity.