Erectile dysfunction (ED) is a complex condition involving psychosocial and biological factors. It is defined as the persistent inability to achieve or maintain penile erection sufficient for satisfactory sexual performance. ED is a common disorder of male sexual function, affecting all age groups with a considerable impact on quality of life. Oral phosphodiesterase type 5 (PDE-5) inhibitors are the first-line treatment options offered to patients with ED. This systematic review of the recent evidence on clinical benefits and harms associated with different pharmaceutical treatments used in the management of male ED is to clarify uncertainties in the field, as well as to identify existing knowledge gaps and directions for future research. The purpose of this evidence report was to review systematically the literature on the diagnosis and pharmaceutical treatments of erectile dysfunction (ED) and to address the following objectives put forth by the Agency for Healthcare Research and Quality (AHRQ) and the American College of Physicians (ACP). The primary objectives of this evidence report were: KQ 1. To determine the clinical utility of routine blood tests - testosterone, prolactin, luteinizing hormone (LH), follicle stimulating hormone (FSH) - in identifying and affecting therapeutic outcomes for treatable causes of ED. KQ 2. To determine the benefits of pharmaceutical treatments for patients with ED. KQ 3. To determine the harms of pharmaceutical treatments for patients with ED. The secondary objectives of this evidence report were: KQ 2a. To explore how patient-specific characteristics (e.g. specific symptoms, age, comorbid conditions) may affect prognosis and treatment success for ED patients. KQ 2b. To determine if the likelihood of treatment success varies by underlying cause of ED. KQ 3a. To identify specific harms, such as nonarteritic ischemic optic neuropathy (NAION) and penile fibrosis of pharmaceutical treatments in patients with ED.