Abstract: OBJECTIVE To explore the influence of gastric lavage with povidone iodine on gastric bacterial colonies and infection rate of patients undergoing endoscopic submucosal dissection (ESD). METHODS A total of 328 patients with early gastric cancer who received ESD in The Second Affiliated Hospital of Xinjiang Medical University from Jan 2014 to Aug 2019 were recruited as the study objects and randomly divided into the study group with 164 cases and the control group with 164 cases. the control group was given the gastric lavage with normal saline before the surgery, while the study group was treated with gastric lavage with povidone iodine. The perioperative indexes, gastric bacterial colony counts, peripheral blood inflammatory factors and incidence of surgery-related complications were observed and compared between the two groups of patients. RESULTS The postoperative white blood cell counts of the study group were(8.73±1.16)×10⁹/L, significantly lower than (9.09±1.38)×10⁹/L of the control group; the body temperature of the study group was (36.31±0.63)℃, significantly lower than (36.57±0.68)℃ of the control group (P<0.05). The Log statistic value of gastric juice flora counts of the study group was (1.48±0.46) after the surgery,significantly lower than (1.85±0.92) of the control group (P<0.05). The C-reactive protein (CRP) level of the study group was (2.27±0.87)mg/L after the surgery,significantly lower than (3.12±1.13)mg/L of the control group(P＜0.05). The incidence rate of postoperative infection of the study group was 0.61%,significantly lower than 4.27% of the study group (P<0.05). CONCLUSION As compared with normal saline, the gastric lavage with povidone iodine before ESD may reduce the postoperative gastric bacterial colony counts and incidence of infection-related complications and facilitate the recovery of the patients.