BACKGROUND: Dextran had been used in free flap reconstruction surgery to increase the patency of anastomotic vessels. This study aimed to evaluate the outcome of perioperative and postoperative dextran in free flap surgery. METHODS: This was a single-center, retrospective study that enrolled 622 patients who received free flap surgery from 2016 to 2020. Propensity score matching was done to minimize the effect of covariance. The outcome included flap-related complications, hospital stay, and mortality. Differences in outcomes were compared between patients treated with dextran and those treated without dextran. RESULTS: After propensity score matching, a total of 378 cases of free flap surgery were included. No difference in total flap failure rate, partial flap failure rate, take-back rate, or major and minor complications were found between the 2 groups. Dextran did not increase the overall complication rate of free flap surgery. Vascular thrombosis remains the most common cause of take-back re-exploration reasons in both the dextran and non-dextran groups. CONCLUSIONS: We found that the use of dextran perioperatively combined with postoperative treatment in microvascular free flap reconstruction showed no statistical difference in flap survival rate and complication rate.