Erectile Dysfunction (ED) is defined as the inability to achieve an erection or maintain an erection sufficient for satisfactory sexual intercourse.

Erectile dysfunction is a very common medical condition with significant consequences. The average age of disease onset is 50 years and the prevalence increases with age. However, any man at any age can also be affected by erectile dysfunction - patients as young as 18-year old have been recorded.

According to Hong Kong Men's Aging Research Association, there are about 152 million men who are affected by erectile dysfunction worldwide. In October 2003, a survey conducted by The Hong Kong Urological Association, of 654 men aged between 40-79 years, revealed that 62% have a certain degree of erectile dysfunction. Based on this survey, the approximate number of men in Hong Kong affected by erectile dysfunction would be almost 910,000.

Atherosclerosis alone accounts for 50% to 60% of ED cases in men aged 60 years and older. ED is present between between 35% and 50% of men with diabetes. ED may also be a predictor for other vascular problems.