Dear Editor,rnWe read with interest of the article written by Park et al.1 They performed a randomized controlled trial to compare efficacy and safety between 50 mg once-daily and 200 mg on-demand dosing use of udenafil for the treatment of type 2 diabetic patients with erectile dysfunction (ED).Their findings indicated that the most common drug-related adverse events (AEs) were flushing (8.9％ vs 2.5％) and headache (3.8％ vs 1.3％) between the on-demand group and the daily-dosed group.Although the authors believed that the udenafil was well-tolerated in both groups,unfortunately,they failed report the total incidence of AEs to assess the safety of the two groups.