Erectile Dysfunction (ED) is the inability to achieve or sustain an erection suitable for sexual intercourse. Problems with erections may stem from medications, chronic illnesses or poor blood flow to the penis.

In order to achieve an erection three conditions must occur: The nerves to the penis must be functioning properly; the blood circulation to the penis must be adequate; there must be a stimulus from the brain. If there is something interfering with any or all of these conditions, a full erection will be prevented.

Failure to achieve an erection less than 20% of the time is not unusual and treatment is rarely needed. However, the failure to achieve an erection more than 50% of the time generally indicates there is a problem requiring treatment.

• At least 20 million American men have some degree of erectile dysfunction, and about one in 10 adult males suffers from ED long-term.
• About 40% of men in their 40s report at least occasional problems getting and maintaining erections. So do more than half (52%) of men aged 40 to 70, and about 70% of men in their 70s.
• Atherosclerosis (hardening of arteries) alone accounts for 50% to 60% of ED cases in men 60 and older. Between 35% and 50% of men with diabetes have ED, and ED may be a predictor for other vascular problems.