Erection is the key, but also the most vulnerable part of male sexuality. It is a process of filling the man’s penis with blood under the influence of various stimuli, in which rigidity of the member is created and sexual intercourse is allowed. In man, erection is achieved entirely by a vascular mechanism, but the process is additionally supported by nervous, hormonal, metabolic and mental factors. The violation of one or more of these units could cause the occurrence of erectile dysfunction. It is defined as a violation in which it is impossible to achieve and/or maintain an erection that allows satisfactory sexual intercourse. If erectile dysfunction is present and lasts for three or more months, it is necessary to undertake clarification of the causes and treatment. The causes are generally divided into mental and organic. The group of organic causes includes neurogenic, vascular, hormonal and anatomical factors. Often a precise differentiation of organic and mental causes could not be achieved. In a number of cases, mental factors are superimposed on organic ones. For the diagnosis of erectile dysfunction, it is necessary to question the patient in detail about the type of dysfunction, the time of its onset, the nature, presence or absence of night and morning erections. Sudden onset of erectile dysfunction is usually psychogenic or due to surgical removal of the prostate (in men with evidence of prostate cancer) or genital trauma. The presence of nocturnal and morning erections is a sign of a man’s preserved sexual function. They are also a sign to distinguish psychogenic from organic erectile dysfunction, in which nocturnal and morning erections are absent. Currently, psychogenic erectile dysfunction is accepted after exclusion of possible organic and medicinal causes of sexual disorders. Vascular causes underlying erectile dysfunction may be suggested by evidence of weakened or absent pulsations in the lower extremities. Rapid relaxation of an erect penis and/or swelling without permanent rigidity indicate insufficient venous compression. The relaxation of the member soon after penetration is characteristic of the so-called. vascular steal syndrome – blood from the filled cavernous bodies of the penis is diverted to the pelvis to cover other oxygen needs. There is a wide range of drugs that can cause erectile dysfunction and therefore the type of drugs that the patient is taking should always be checked and taken into account. NEWS_MORE_BOX An International Index of Erectile Function has been developed. It is a detailed questionnaire including 5 sections relating to the main areas of male sexuality: erectile function, orgasm, sexual desire, pleasure from intercourse, general satisfaction from sexual life and from relationships with the partner. This questionnaire serves to determine the degree of sexual dysfunction,and is also an indicator for assessing the effect of treatment. The diagnostic package for men with erectile dysfunction includes a thorough examination, including examination for perineal sensitivity, pulsations of the lower extremities, determination of secondary genital marks, palpation of the penis, and measurement of the size and consistency of the testicles. From the laboratory tests, it is necessary to examine a complete blood count, lipid profile, blood sugar and glycated hemoglobin, serum testosterone and prolactin levels. The goal of the treatment is to achieve an erection that allows sexual intercourse, which does not last more than 1 hour. The ideal treatment should meet the following requirements: be easy to use, be non-invasive, painless and highly effective with minimal side effects. In the next article, we will pay more attention to the remedies for erectile dysfunction.