Erectile dysfunction (ED) due to diabetes mellitus is closely related to a variety of psychosomatic, vascular, neurological and endocrine factors. Studies have concluded that diabetes-induced neuropathy and vasculopathy are the main causes of ED. In 1992, an NIH expert meeting determined that diabetes is an important cause of sexual dysfunction, of which ED is the most common, and the incidence of ED in diabetic patients is 1 to 4 times that of non-diabetic patients. The prevalence of ED among diabetic patients in China is as high as 60% or more, and its incidence increases with age, prolongation of the disease course and the emergence of other neurovascular complications. In addition, diabetes may also induce ED by reducing local nitric oxide levels, increasing glycosylation end products, and reducing sex hormone levels, etc. At present, diabetic ED should be treated first for the primary lesion, including a series of corresponding measures such as improving lifestyle, applying oral hypoglycemic drugs and insulin. The first line of treatment for diabetic ED is phosphodiesterase (PDE5) inhibitors (such as sildenafil, vardenafil, tadalafil, etc.), which are mainly found in the human penile tissue. Sildenafil, vardenafil and tadalafil can significantly improve symptoms and achieve and maintain satisfactory erectile capacity in patients with diabetic ED, even in patients with poor glycemic control and severe complications. Sildenafil (Viagra) is rapidly absorbed, reaching peak plasma concentration in 30-120 minutes when taken orally in fasting state, with a mean half-life of 4 hours. The recommended dose of sildenafil for most patients is 50 mg, taken one hour before sexual activity, and can actually be taken at any time from 0.5 to 4 hours before sexual activity. Based on efficacy or tolerability, the dose may be increased to 100 mg (the maximum recommended dose) or decreased to 25 mg, taken up to once daily. Vardenafil (Elidel) has a similar plasma time to peak and half-life as sildenafil, and the recommended starting dose is 10 mg, taken approximately 25 to 60 minutes prior to sexual activity. Depending on efficacy and tolerability, the vardenafil dose may be increased to 20 mg (maximum recommended dose) or decreased to 5 mg, taken up to once daily. Tadalafil tablets (cialis) have a peak plasma time of about 2 hours, a mean half-life of 17.5 hours, and a longer duration of action. The recommended dose is generally 10 mg, but may be increased to 20 mg, and the maximum frequency of administration is once daily. Common adverse reactions to these three drugs include mild to moderate headache, flushing, dyspepsia, nasal congestion, etc. Some patients experience greenish vision, and cardiovascular adverse reactions include increased blood pressure, tachycardia and palpitations, but the incidence is low. These drugs are used with caution in cardiovascular patients and should not be combined with nitrate drugs such as nitroglycerin. Alpha-adrenergic receptor antagonists can competitively block alpha-adrenergic receptors and diastole norepinephrine-mediated vascular smooth muscle contraction and can be used in the treatment of ED. Oral yohimbine has been used to treat ED for many years, but the clinical application is not certain. Yohimbine has demonstrated significant efficacy in in vitro trials, and penile corpus cavernosum injections can significantly increase intracavernosal pressure and erection duration with no significant effect on blood pressure. The above drugs are used only for the treatment of psychogenic and mild organic ED, with common adverse effects of nausea, headache, and vertigo. Dopaminergic receptor agonists (apomorphine) can induce penile erection in rats as well as in healthy or ED patients, however, research on dopamine D2 receptor agonist drugs for ED has been slow to develop because of pharmacokinetic and adverse effects. The clinical application of apomorphine is also unsatisfactory, such as poor oral effect and short duration, among which the most unsatisfactory are its adverse effects, most commonly such as nausea, vomiting, sweating and vertigo, and even severe hypotension during local injection. Therefore, apomorphine is currently used mainly for the treatment of psychogenic ED. Androgens can be used in patients with diabetic ED, and there is a significant improvement in ED symptoms in patients taking oral testosterone. However, most studies have shown that androgen replacement therapy alone given to patients with diabetic ED is ineffective, but is effective in combination with phosphodiesterase (PDE5) inhibitors.