Penile erectile dysfunction (ED) is defined in Western medicine as the persistent inability of the penis to achieve or maintain an erection sufficient to obtain a satisfactory sexual life. In Chinese medicine, it is defined as the inability to attain or maintain an erection for satisfactory sexual intercourse. One out of every two men over 40 years of age will suffer from different degrees of ED. The causes can be broadly classified into three categories: 1. Organic (caused by vascular, neurological, cavernous abnormalities or injuries). 2. 2, psychological (anxiety, depression and other erectile center level inhibition). 3, mixed type (organic and psychological at the same time).