Objective To evaluate the effect of perioperative probiotics or synbiotics on the incidence of postoperative infections following major liver surgery. Design Meta-analysis Data sources PubMed, Embase, Scopus, and the Cochrane Library for relevant English-language studies published up to February 21st, 2024. Eligibility criteria Randomized controlled trials evaluating perioperative probiotics or synbiotics for preventing postoperative infections in patients undergoing major liver surgery. Data extraction and synthesis Outcomes included postoperative infection incidence, antibiotic therapy duration, length of stay in intensive care unit (ICU) and hospital. A random-effect model was adopted for the meta-analysis. The quality of included studies was evaluated using the Cochrane risk of bias tool. Results Ten studies involving 588 patients were included. Pooled analyses revealed that perioperative probiotics or synbiotics significantly reduced postoperative infection incidence (RR 0.36, 95% CI [0.24–0.54], P