Objective:To investigate the effect of the lactitol powder combined with piperacillin sodium and tazobactam sodium in patients with spontaneous bacterial peritonitis (SBP), and the influence on the body microenvironment.Methods:The clinical data of 135 patients with SBP from January 2017 to December 2019 in Huxi Hospital Affiliated Jining Medical College were retrospectively analyzed. Among them, 68 patients were treated with lactitol powder combined with piperacillin sodium and tazobactam sodium (observation group), 67 patients were treated with piperacillin sodium and tazobactam sodium (control group). The curative effect was compared between 2 groups. The recovery time of clinical symptoms and signs (disappearance time of abdominal pain, disappearance time of abdominal distension, disappearance time of abdominal tenderness, recovery time of body temperature and recovery time of ascites white blood cell), liver function indexes (alanine aminotransferase, ALT; total bilirubin; albumin; aspartate aminotransferase, AST), microcirculation indexes (haptoglobin; procalcitonin; interleukin-6, IL-6; neutrophil gelatinase-associated lipocalin, NGAL), intestinal mucosal permeability indexes (endotoxin, blood ammonia, diamine oxidase) and adverse reactions (diarrhea, nausea and skin itching) were recorded.Results:The total effective rate in observation group was significantly higher than that in control group: 95.59% (65/68) vs. 82.09% (55/67), and there was statistical difference ( P<0.05). The disappearance time of abdominal pain, disappearance time of abdominal distension, disappearance time of abdominal tenderness, recovery time of body temperature and recovery time of ascites white blood cell in observation group were significantly shorter than those in control group: (6.15±1.34) d vs. (8.26±1.19) d, (5.34±1.29) d vs. (7.18±1.35) d, (7.59±1.65) d vs. (9.86±1.80) d, (5.28±1.20) d vs. (6.39±1.12) d and (10.87±2.25) d vs. (12.18±1.67) d, and there were statistical differences ( P<0.01). The ALT, total bilirubin, AST, haptoglobin, procalcitonin, IL-6, NGAL, endotoxin, blood ammonia and diamine oxidase 1 and 2 weeks after treatment in observation group were significantly lower than those in control group, and there were statistical differences ( P<0.01); there was no statistical difference in albumin between 2 groups ( P>0.05). There was no statistical difference in incidence of adverse reactions between2 groups ( P>0.05). Conclusions:The lactitol powder combined with piperacillin sodium and tazobactam sodium for SBP patients can more significantly improve the liver function and intestinal mucosal permeability, and promote the body microenvironment and the recovery of symptoms.