BackgroundPeristomal wound infection is a common complication in patients receiving percutaneous endoscopic gastrostomy (PEG). The main reason for peristomal infection might be the oral microbes coating the gastrostomy tube during implantation. Povidone-iodine solution can be applied for skin and oral decontamination. We designed a randomized controlled trial to test the effectiveness of a Betadine® (povidone-iodine) coated gastrostomy tube to reduce peristomal infection after percutaneous endoscopic gastrostomy.MethodsA total of 50 patients were randomized to Betadine and control groups (25 patients in each group) from April 2014 to August 2021 at a tertiary medical center. All patients received the pull method for PEG implantation using a 24-french gastrostomy tube. The primary endpoint was peristomal wound infection rate 2 weeks after the procedure.ResultsChanges in Neutrophil/Lymphocyte ratio (N/L ratio) and C-Reative protein (Delta CRP) at 24 h after PEG were higher in the control group than in the Betadine group (N/L ratio, 3.1 vs. 1.2, p = 0.047; CRP, 2.68 vs.1.16, p = 0.009). The two groups did not differ in post-PEG fever, peristomal infection, pneumonia, or all-cause infection. Delta CRP could predict peristomal infection and all-cause infection within 2 weeks (AUROC 0.712 vs. 0.748;p= 0.039 vs. 0.008). The best cut-off-point of Delta CRP for the diagnosis of peristomal wound infection was 3 mg/dl.ConclusionThe betadine coating gastrostomy tube method could not reduce peristomal infection after percutaneous endoscopic gastrostomy. CRP elevation of less than 3 mg/dl may be used to exclude the potential peristomal wound infection.Trial registrationNCT04249570 (https://clinicaltrials.gov/ct2/show/NCT04249570).Supplementary InformationThe online version contains supplementary material available at 10.1186/s12876-023-02702-w.