Erectile dysfunction is defined as the inability to get or keep an erection sufficient enough for sexual intercourse. There are many causes of erectile dysfunction and they include: diabetes, chronic renal failure, atherosclerosis, neurological disorders, nerve or vessel damage as a result of operation or irradiation etc. Certain drugs including hypertensive drugs, antidepressants, tranquilizers etc can also cause erectile dysfunction. Psychological factors such as stress, anxiety, guilt, depression, low self-esteem, and fear of sexual failure can also contribute to the disease. Lifestyle choices that contribute to heart disease and vascular problems also raise the risk of erectile dysfunction. Smoking, being overweight, and avoiding exercise are possible causes of ED.