BackgroundA number of published comparative studies have been conducted to evaluate the efficacy and safety of intraoperative mitomycin C (MMC) in endoscopic dacryocystorhinostomy (EN-DCR). However, results have not always been consistent. Therefore, we carried out a meta-analysis to compare the clinical results of EN-DCR with and without MMC.Methods and FindingsA comprehensive literature search of Cochrane Library, PubMed and EMBASE to identify relevant trials comparing EN-DCR with and without MMC. Eleven studies including 574 eyes were included in this meta-analysis. The success was defined as patency of the nasolacrimal canal and symptomatic improvement. There was significantly higher success rate in the MMC group in comparison with control group [RR = 1.12, 95% CI (1.04, 1.20), P = 0.004]. A sensitivity analysis after the non-randomized controlled trials were excluded from the meta-analysis demonstrated no differences compared with the overall results. Subgroup analyses showed that MMC group had a significantly higher success rate than control group in primary and revision EN-DCR, and EN-DCR without silicone intubation, but no difference in the subgroup of with silicone intubation. The size of the osteotomy site was bigger in the MMC group compared to the control group at 3 months [WMD = 7.65, 95% CI (0.33, 14.98), P = 0.041] and 6 months [WMD = 9.28, 95% CI (2.45, 16.11), P = 0.008] after surgery. However, there was statistically significant difference in the osteotomy surface area between the two groups at 12 months after surgery [WMD = 11.63, 95% CI (−1.04, 24.29), P = 0.072].ConclusionIntraoperative MMC application seems to be a safe adjuvant that could reduce the closure rate of the osteotomy and enhance the success rate after both primary and revision EN-DCR.Trial RegistrationClinicalTrials.gov NCT01772277