Siwu Decoction is composed of four traditional Chinese medicines: Angelica sinensis, Chuanxiong rhizome, white peony root and rehmannia glutinosa. It is a prescription with the main function of nourishing and regulating blood. It is known as "the general prescription for all blood diseases" and " A special agent for regulating the liver meridian and regulating blood."

Judging from the prescription of Siwu Decoction, Rehmannia glutinosa mainly nourishes blood and has the effect of nourishing kidney and essence; Angelica sinensis nourishes blood, activates blood circulation, and nourishes yang in yin. The single medicine has the functions of aphrodisiac and stimulating yang. Ligusticum chuanxiong enters the blood and regulates the qi in the blood; peony astringes yin and nourishes blood. Ligusticum chuanxiong and peony can relieve vascular spasm and increase arterial blood supply. All prescriptions are blood-dispensing medicines and constitute an important agent for treating blood. Since the basic foothold of traditional Chinese medicine in treating reproductive system diseases is "male sperm and female blood", and "semen and blood have the same origin", that is, both semen and blood are the basic substances of human body fluids. Menstruation and blood can transform into each other, and blood replenishment can help It is used to promote the production of sperm, and the essence filling itself has the effect of nourishing blood. It can be seen that the blood-tonifying and blood-regulating effect of Siwu Decoction and the basic theory of "the homology of essence and blood" provide a reliable basis for the treatment of impotence.

The impotence suffered by middle-aged people is mostly related to coronary atherosclerosis and cerebral stroke, and impotence is often a local manifestation of systemic vascular disease. Therefore, Siwu Decoction can treat vascular impotence. It has better therapeutic effect.