Erectile dysfunction (ED) is the inability to achieve or maintain an erection sufficient for satisfactory sexual intercourse. 152 million people worldwide suffered from varying degrees of ED in 1995, and it is expected that by 2025 there will be 322 million ED patients worldwide, including 113 million in Asia. The onset of ED is age-related, with severe or complete erectile dysfunction accounting for 5% of men in their 40s and 15% of men in their 70s, with milder erectile dysfunction being more common. Vardenafil hydrochloride, chemically known as 2-[2-ethoxy-5-(4-ethyl-piperazine-1-sulfonyl)-phenyl Vardenafil hydrochloride, chemically 2-[2-ethoxy-5-(4-ethyl-piperazine-1-sulfonyl)-phenyl]-5-methyl-7-propyl-3H-imidazo[5,1-f] -[1,2,4]triazol-4-one monohydrochloride, a potent, highly selective, novel oral PDE5 inhibitor developed at Bayer headquarters, potently enhances the effects of endogenous nitric oxide, causing an increase in cGMP concentration in the penile corpus cavernosum, leading to smooth muscle relaxation and increased blood flow within the penile corpus cavernosum, which both promotes smooth muscle relaxation and causes penile erection. Pharmacological studies have found that vardenafil is approximately 10 times more potent than sildenafil in inhibiting PDE5 under the same conditions, while the effective dose is 5-10 times lower. In a 12-week, double-blind, placebo-controlled phase II trial enrolling 601 patients with mild to moderate ED, on-demand vardenafil 5 mg, 10 mg, and 20 mg significantly improved the ability of patients to achieve and maintain an erection sufficient for sexual intercourse compared to the placebo group (p < 0.001). In a North American phase III study conducted at 60 centers in the United States and Canada, all patients with ED of varying etiology and severity were randomized to placebo, vardenafil 5mg, 10mg, or 20mg for 26 weeks, and of those who completed 26 weeks of treatment, 85%, 80%, and 65% of patients in the vardenafil 20mg, 10mg, and 5mg groups, respectively, showed Erectile function improved in 85%, 80% and 65% of patients in the vardenafil 20 mg, 10 mg and 5 mg groups, respectively, compared to 28% in the placebo group (P < 0.0001). In a 12-week phase III clinical study at 26 centers in Europe, vardenafil 5mg, 10mg and 20mg were significantly more effective than the placebo group in treating patients with ED of various etiologies as assessed by IIEF-EF scores, Sexual Intercourse Questionnaire questions 2 and 3 [SEP2/SEP3] and GAQ. Numerous clinical trials of vardenafil for the treatment of ED have been completed worldwide, with statistically significant differences in all major efficacy indicators against placebo controls (including special populations, e.g., diabetes, post-total prostatectomy), demonstrating the clinical therapeutic significance of vardenafil in improving erectile dysfunction. The safety profile of vardenafil was also satisfactory in all clinical trials and laboratory safety profiles, and the results of the study demonstrated that the drug was well tolerated, with most adverse events (headache, vasodilation, dyspepsia, nasal congestion) being within the range of those commonly associated with PDE5 inhibitors. The inductive statistical analysis of the primary and secondary efficacy indicators in 88 patients in our central trial showed that all three doses of vardenafil, 5 mg, 10 mg and 20 mg, showed significant efficacy compared to placebo, which is generally consistent with the results of foreign phase II and III clinical studies of vardenafil. Most of the adverse events were mild and most of them resolved without treatment, and the time of remission was mostly on the day of administration. One serious adverse event occurred in the placebo group in our center and was judged to be unrelated to the study drug. The results suggest that all three doses of vardenafil (5 mg, 10 mg, and 20 mg) are safe and effective drugs for the treatment of ED.