Si Wu Tang — Four-Substance Decoction

On this page

1. Overview
2. TCM pattern
3. Key herbs
4. Formula actions
5. Conditions treated
6. Cautions

Overview

Si Wu Tang — Four-Substance Decoction — is the foundational Blood tonic formula in the entire canon of Chinese herbal medicine. First recorded in the Tang Dynasty (618–907 CE) in the Xian Shou Li Shang Xu Duan Mi Fang, it consists of just four herbs that together nourish Blood, invigorate Blood and regulate the Liver. It is the most important and most widely prescribed formula for Blood deficiency in women and forms the base from which many other important formulas are derived, including Ba Zhen Tang (Eight Treasure Decoction), Tao Hong Si Wu Tang and Gui Zhi Fu Ling Wan variants. Its classical name — Si Wu (Four Substances) — simply reflects its composition of four herbs.

TCM pattern

Si Wu Tang is prescribed for Liver Blood deficiency, characterised by: pale or sallow complexion, pale lips and fingernails, dizziness and blurred vision, palpitations, insomnia, dry skin and hair, numbness or tingling of the limbs, irregular or scanty menstruation, delayed menstrual cycle, a pale tongue, and a thin, choppy pulse. The formula also has a mild Blood-invigorating action, making it suitable for Blood deficiency with a mild stasis component.

Key herbs

1. Shu Di Huang (prepared Rehmannia root) — the principal herb; powerfully nourishes Blood and Yin; fills the Essence; the most important Blood tonic in TCM
2. Bai Shao (Paeonia lactiflora root, white) — nourishes Blood and preserves Yin; calms the Liver and relieves spasm; softens the Liver’s interaction with the formula
3. Dang Gui (Angelica sinensis root) — nourishes and invigorates Blood simultaneously; regulates menstruation and relieves pain; the leading herb for women’s Blood conditions
4. Chuan Xiong (Ligusticum chuanxiong rhizome) — invigorates Blood and moves Qi; prevents the nourishing herbs from causing stagnation; the chief Blood-moving herb for headache and menstrual pain

The elegance of this formula lies in the pairing of tonic and moving herbs: Shu Di Huang and Bai Shao nourish and contain Blood, while Dang Gui and Chuan Xiong invigorate and move it. This balance tonifies without causing stagnation and moves without damaging Blood.

Formula actions

1. Nourishes the Blood
2. Regulates the Liver
3. Improves Blood circulation
4. Regulates menstruation

Conditions treated

1. Irregular menstrual cycle — delayed, scanty or pale periods from Blood deficiency; the foundational formula for menstrual Blood deficiency
2. Dysmenorrhoea (painful periods) with Blood deficiency and mild stasis
3. Amenorrhoea from Blood deficiency
4. Post-partum recovery — rebuilding Blood after childbirth and blood loss
5. Anaemia and chronic Blood deficiency with pallor, fatigue and dizziness
6. Insomnia and palpitations from Liver Blood deficiency failing to anchor the Mind
7. Dry skin, hair loss and brittle nails from Blood deficiency
8. Support during IVF and fertility treatment to nourish Blood and support endometrial development

Cautions

Use with caution during pregnancy (Chuan Xiong and Dang Gui have uterotonic properties). Not suitable as the sole formula where significant Blood stasis, excess Heat, Damp-Phlegm or Yang deficiency is the primary pattern. Shu Di Huang can burden digestion in patients with Spleen deficiency — in such cases, the formula may be modified by adding Sha Ren or Chen Pi to assist digestion.

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