Erectile dysfunction (ED) can be a total inability to achieve erection for sexual intercourse, an inconsistent ability to do so, or a tendency to sustain only brief erections. It is estimated that between 15 million and 30 million American men experience erectile dysfunction. In older men, the cause is usually something physical like disease, injury, or side effects of drugs; but any disorder that causes injury to the nerves or impairs blood flow in the penis can potentially cause erectile dysfunction. Some treatment options for erectile dysfunction include medications, counseling, implanted devices, and lifestyle changes (such as quitting smoking and losing excess weight).