The ratio of the fecal short-chain fatty acid (SCFA) to lactic acid concentrations (APB-L ratio) is a useful indicator for the healthiness of the intestinal microenvironment. A recent study indicated that the low APB-L ratio can be a predictor of postoperative infectious complications (POICs) in patients undergoing pancreaticoduodenectomy. However, the predictive power of the APB-L ratio in other highly invasive surgeries, such as esophagectomy, is still unclear. This study investigated whether the APB-L ratio can be a sensitive predictor of POICs in patients undergoing esohpagectomy. A total of 129 patients undergoing esohpagectomy with gastric conduit reconstruction were included in this study. Preoperative fecal samples were analyzed for SCFA and lactic acid concentrations. The associations between clinical characteristics, POICs, and the APB-L ratio were analyzed. Preoperative and intraoperative risk factors for POICs were explored via multivariate logistic regression analysis. Postoperative infectious complications were observed in 34 patients (26%), including surgical site infections in 18 patients (14%). A low APB-L ratio was significantly associated with higher POICs and surgical site infections risk (both p < 0.05). A low APB-L ratio was identified as an independent risk factor for POICs, with an odds ratio of 3.62 (95% confidence interval, 1.44-9.10, p = 0.006). The APB-L ratio measured with preoperative fecal organic acid concentrations is useful to assess the risk of POICs for esohpagectomy. The results also imply the importance of maintaining a healthy intestinal metabolism (thus high APB-L ratio) to reduce POICs before highly invasive surgery.