Although intracavernous penile injection (ICI) has been widely used as a screening test for various erectile dysfunctions, the limitations of the ICI test have been questioned with its high false negative rate in patients with psychogenic erectile dysfunction. In some studies, measurement of norepinephrine levels (NE) in penile blood at the time of intracavernous penile injection suggested an increase (statistically significant) in patients with psychogenic erectile dysfunction compared to normal subjects and those with vascular erectile dysfunction. It also suggests that the negative results in patients with psychogenic erectile dysfunction receiving intracavernous penile injections may be due to excessive NE secretion in the cavernous body, which inhibits the dilatory function of vasoactive drugs on cavernous smooth muscle. Improve ICI medication (choose compounded preparations, especially containing α-blocker components); or injection with hand heavy rain (non-ejaculatory state) methods can reduce the occurrence of false negative.