American Yugen 1 can selectively inhibit phosphodiesterase 5(PDE5) on the cavernous artery of penis, dilate the cavernous artery of penis, increase the blood flow of the cavernous artery of penis, make the cavernous body congested and dilated, effectively solve the problem of penile weakness, increase the hardness of penis erection, achieve the effect of treating impotence, and avoid the risk that the existing products are easy to induce abnormal erection of penis.