Judging from the prescription meaning of Siwu decoction, Radix Rehmanniae Preparata mainly enriches blood, which has the function of tonifying kidney and replenishing essence. Angelica sinensis can replenish blood and promote blood circulation, nourish yin and tonify yang. Single medicine has the function of strengthening yang and rising yang. Chuanxiong enters the blood and divides the qi in the blood; Radix Paeoniae Alba can astringe yin and nourish blood, while Rhizoma Chuanxiong and Radix Paeoniae Alba can relieve vascular contracture and increase arterial blood supply. The whole prescription belongs to blood medicine, which constitutes the essential medicine for treating blood. Because the basic position of traditional Chinese medicine in treating reproductive system diseases is that "men's sperm and women's blood" and "essence and blood are homologous", that is, essence and blood are the basic substances of human body fluids, and menstrual blood can be transformed into each other, and enriching blood helps to promote the production of essence and qi, while replenishing essence itself has the function of nourishing blood.
Chuanxiong is pungent and warm, acting on the liver and gallbladder. It has the effects of promoting qi circulation, promoting blood circulation, calming the nerves, dispelling pathogenic wind, relieving pain, soothing the liver and relieving depression.
Paeonia lactiflora is sour, bitter and slightly cold. It acts on the liver and spleen and has the functions of nourishing blood, moistening dryness, relieving pain, soothing the liver and strengthening the spleen.
Rehmannia glutinosa is sweet and slightly warm. It acts on the heart, liver and kidney, and has the functions of enriching blood, nourishing yin, replenishing essence and marrow. However, Radix Rehmanniae Preparata has high sugar content, nourishing and consistency, and it is not suitable for people with indigestion and diarrhea.
Angelica sinensis is sweet, pungent and warm, which acts on the liver, heart and spleen, and has the functions of enriching blood, regulating menstruation, promoting blood circulation and relieving pain. Contains vitamin B 12 and folic acid, and has the effects of resisting pernicious anemia and promoting wound healing.