Objective: This systematic review and meta-analysis were performed to evaluate the efficacy of preoperative dutasteride treatment for reducing surgical blood loss in patients undergoing transurethral resection of the prostate (TURP). Methods: A systematic search was performed from the electronic databases including PubMed, EMBASE, and Cochrane Library by May 2016. We followed the search strategy based on Preferred Reporting Items for Systematic Reviews and Meta-analysis statement when examining the literature. Identified articles were strictly appraised for quality and relevance. Results: Five randomized controlled trials (RCTs) and 5 retrospective cohort studies involving 1,022 patients with benign prostate hyperplasia were analyzed based on the inclusion criteria. Pooled analysis revealed that preoperative treatment with dutasteride had a significantly smaller decrease in hemoglobin (weighted mean difference WMD] -0.47, 95% CI -0.70 to -0.24, p < 0.0001) and hematocrit levels (WMD -1.03, 95% CI -1.73 to -0.33, p = 0.004); However, no significant difference has been found in terms of the total blood loss during TURP and blood loos per gram of resected prostatic tissue, the weight of resected prostate tissue, the microvessel density of the prostate, and the transfusion rate between the dutasteride and the control group. Conclusions: This systematic review and meta-analysis indicate that preoperative treatment with dutasteride could reduce surgical bleeding during TURP, but the findings of this study should be further confirmed by well-designed prospective RCTs with a larger patient series. (C) 2016 S. Karger AG, Basel