Abstract: Objective To explore the influence of hydrogen sulfide on the intestinal biological barrier, by applying exogenous hydrogen sulfide and hydrogen sulfide synthase inhibitor for the treatment of rats with severe burn injury. Methods One hundred and four SD rats were divided into sham injury (SI, n=8), burn control (BC, n=32), sodium hydrosulfide (SH, n=32), and propargylglycine groups (PPG, n=32) according to the random number table. Rats in group SI were sham injured without fluid resuscitation. Rats in the latter 3 groups were inflicted with 30% TBSA full–thickness scald (referred to as burn below) on the back and intraperitoneally injected with 40 mL/kg balanced salt solution immediately after injury. Rats in groups SH and PPG were respectively intraperitoneally injected with SH (56 μmol/kg) and PPG (45 mg/kg) within 1 hour post injury. From post injury day (PID) 2, SH (56 μmol/kg) and PPG (45 mg/kg) were respectively intraperitoneally injected once a day to rats in groups SH and PPG. Eight rats from groups BC, SH, and PPG were sacrificed on PID 2, 7, 14 and 21, and ceca samples were collected. Ceca samples were added to the appropriate culture medium after being homogenized and diluted, for the culture of Bifidobacterium, Lactobacillus, Enterococcus, Enterobacter, and Candida albicans. The content of bacteria was calculated after the bacteria number was counted. The same procedure was performed for rats in group SI. Data were processed with logarithmic function, one–way analysis of variance, analysis of variance of factorial design, and SNK–q test. Results On each PID, the content of Bifidobacterium and Lactobacillus in the ceca of each group with burned rats was less than that of group SI (with q values from 4.12 to 20.74, P values below 0.05); while the content of Enterococcus, Enterobacter, and Candida albicans was more than that of group SI (with q values from 2.84 to 68.29, P values below 0.05). Compared with that of group BC, the content of Bifidobacterium and Lactobacillus in the ceca of rats in group SH were increased on each PID (with q values from 2.88 to 17.57, P values below 0.05). In group SH, the content of Bifidobacterium peaked as (6.54±0.35) lg (CFU/g) on PID 7, the content of Lactobacillus peaked as (7.25±0.71) lg (CFU/g) on PID 21. Compared with that of group BC, the content of Enterococcus, Enterobacter, and Candida albicans in the ceca of rats in group SH was reduced on each PID (with q values from 2.79 to 29.59, P values below 0.05). Compared with that of group BC, the content of Bifidobacterium and Lactobacillus in the ceca of rats in group PPG was decreased on each PID (with q values from 2.82 to 46.56, P values below 0.05); while the content of Enterococcus, Enterobacter, and Candida albicans was significantly increased on each PID (with q values from 2.93 to 41.42, P values below 0.05). In group PPG, the content of Enterococcus peaked as (9.41±0.22) lg (CFU/g) on PID 21, the content of Enterobacter peaked as (9.96±0.24) lg (CFU/g) on PID 14, and that of Candida albicans peaked as (3.94±0.84) lg (CFU/g) on PID 14. Conclusions Exogenous hydrogen sulfide can subdue the growth of pathogenic bacteria while promote that of probiotics, thus helping maintain the integrity of intestinal biological barrier of rats with burn injury.