Fecal microbial transplantation is to transplant functional microbiota from the feces of healthy people into the gastrointestinal tract of patients, reconstruct new intestinal microbiota, and realize the treatment of intestinal and extra-intestinal diseases. Compared with ordinary commercial probiotics, FMT is more consistent with the composition of the intestinal microecological structure and can recover intestinal flora to the maximum extent and faster. FMT increases intestinal bacteria production function and helps to restore the systemic immune response so that sepsis pathogens are removed. The aim of this trial was to investigate the clinical effect of FMT in the treatment of patients with severe infections.