Applying Mitomycin C topically after endoscopic sinus surgery could reduce the risk of nasal synechiae and maxillary sinus ostium stenosis in short term by 66% and 74%, respectively. The treatment effects may be more beneficial in patients aged 40 years or younger or in patients without history of revision. However, our results were based on pooling trials with questionable methodological quality. Further trials with good research methodology and long-term follow-up should be conducted to confirm our results.