Rongtong Dictionary · Formula

Siwu Decoction: Origins, the Logic of Nourishing and Regulating Blood, the Taohong Siwu Lineage, and Modern Evidence

Published and reviewed 2026-07-09

Siwu (Four Substances) Decoction is the foundational blood-nourishing and blood-regulating formula and the classic 'first formula of gynecology.' It first appeared in the Tang physician Lin Daoren's Xianshou Lishang Xuduan Mifang (originally for traumatic blood stasis) and was established as a common gynecological formula by the Song Taiping Huimin Heji Jufang. Built from prepared rehmannia, angelica, white peony, and chuanxiong — 'tonifying without stagnation, enriching without cloying' — it treats the 'constructive-blood deficiency-and-stagnation pattern.' It is both a model of blood-tonifying compatibility (pairing blood-nourishing with blood-moving herbs) and the mother of over eight hundred derivative formulas; modern research offers randomized trials in primary dysmenorrhea, though a 'blood-deficiency pattern' remains a traditional construct, never the modern diagnosis of anemia.

Origin: from a trauma formula to the 'first formula of gynecology'

The origins of Siwu Decoction (also called Disui Tang or Da Chuanxiong Tang) are winding. It first appeared in the Tang physician Lin Daoren's Xianshou Lishang Xuduan Mifang, where the text says 'for severe injury with static blood in the intestines' — it began, remarkably, as a trauma formula for falls, blows, and abdominal blood stasis. The Northern Song government Taiping Huimin Heji Jufang later included it under 'treating women's various diseases,' for thoroughfare-and-conception-vessel deficiency, irregular menses, and abdominal pain, thereby establishing it as the 'first formula of gynecology' and the 'first formula for nourishing blood and regulating menses.' Later ages derived over eight hundred formulas from it, an influence of enormous reach.

A deeper origin: according to the modern scholar Zhang Shanlei, Siwu is a modification of Zhang Zhongjing's Jiao'ai decoction (Xiong-gui Jiao'ai Tang) in the Jinkui Yaolue — Lin Daoren removed the blood-nourishing, hemostatic, womb-warming donkey-hide gelatin, mugwort, and licorice, substituted prepared for raw rehmannia and fixed white peony, kept angelica and chuanxiong, and thus made Siwu, turning a 'nourish blood, stop bleeding, regulate menses, calm the fetus' formula into a 'treat blood-deficiency-and-stagnation' one. The original four herbs are in equal parts (three qian per dose). This page identifies the entity only and offers no dose conversion or preparation procedure.

Composition: a paradigm of 'nourish blood without stagnation, move blood without harm'

Four ingredients: prepared rehmannia (Rehmanniae Radix Praeparata, sovereign), angelica (Angelicae Sinensis Radix, minister), white peony (Paeoniae Radix Alba, assistant), and chuanxiong (Chuanxiong Rhizoma, assistant-envoy). (Note: textbooks differ slightly on the exact role assignment, some taking rehmannia as sovereign, others angelica; this page follows one mainstream account.)

In the textbook reading, prepared rehmannia nourishes yin and blood and fills essence as sovereign; angelica supplements blood, nourishes the liver, and harmonizes blood to regulate menses as minister, the two being the core of blood tonification; white peony nourishes blood, softens the liver, and harmonizes the constructive as assistant; and chuanxiong invigorates blood and moves qi as assistant-envoy — chuanxiong is the finishing touch: adding one acrid-warm, coursing herb among three enriching blood-nourishers makes the whole 'nourish blood without stagnation, move blood without harm,' movement within stillness, coursing within tonification. Zhang Bingcheng's Chengfang Biandu praised this logic. The whole 'tonifies without stagnation, enriches without cloying,' the four harmonizing constructive blood. Rehmannia and white peony are the 'blood-within-blood herbs' (guarding), angelica and chuanxiong the 'qi-within-blood herbs' (moving) — one guards, one moves, stillness and motion well matched. This 'blood-tonics must be paired with blood-movers' idea is the key to Siwu transcending mere enrichment as a paradigm of formula compatibility.

Pattern, not disease: 'blood-deficiency pattern' is not 'anemia'

The textbook mechanism is 'constructive-blood deficiency-and-stagnation.' Constructive-blood depletion with inhibited flow brings a sallow complexion, pale lips and nails without luster, dizziness, and palpitations with insomnia; blood deficiency disordering the thoroughfare and conception vessels brings scant, pale menses, amenorrhea, or abdominal pain; a pale tongue and thin or thin-choppy pulse are all signs of blood deficiency with inhibited flow. The method is 'nourish and regulate blood.'

Here 'constructive blood' and 'blood deficiency' are traditional functional constructs. It must be clarified: TCM's 'blood-deficiency pattern' is a functional state differentiated from a cluster of signs (complexion, lips and nails, dizziness and palpitations, menses, tongue and pulse) and is emphatically not a synonym for the modern 'anemia' diagnosed by hemoglobin/red-cell count — those with a blood-deficiency pattern need not have an abnormal blood count, and the anemic need not present as TCM 'blood deficiency.' Although the textbook lists Siwu as 'now commonly used for anemia and irregular menses,' the qualifier 'belonging to constructive-blood deficiency-and-stagnation' is crucial. Equating 'nourish blood' with 'treat anemia' and using Siwu whenever there is 'anemia' is a common error; iron-deficiency and other anemias have definite causes requiring cause-directed treatment.

Historical development: the 'ancestor of blood formulas' with eight hundred descendants

Siwu's stature comes from its role as the mother of blood-nourishing and blood-regulating formulas, with over eight hundred derivatives. The most famous: adding peach kernel and safflower yields Taohong Siwu Tang (stronger blood-invigorating stasis-dispelling, for dysmenorrhea and irregular menses with blood deficiency plus stasis, one of the most-researched Siwu relatives); Siwu with Sijunzi yields Bazhen Decoction (dual qi-and-blood tonification); Bazhen with astragalus and cinnamon yields Shiquan Dabu Decoction; Siwu with astragalus and ginseng yields Shengyu Decoction (boost qi, contain blood); Siwu with gelatin and mugwort (in effect returning to its ancestral Jiao'ai) treats flooding and fetal stirring; adding cyperus yields Xiangfu Siwu Tang (regulate qi and menses). There are also cold-clearing and repletion/deficiency modifications such as Qinlian Siwu and Yuzhu San.

Siwu's modifications show great compatibility wisdom: for blood heat, substitute raw rehmannia and red peony (cool blood); for blood stasis, add peach kernel and safflower (dispel stasis); for marked deficiency, heavily use rehmannia and angelica (enrich); for concurrent qi deficiency, add ginseng and astragalus (dual tonification). This 'one base formula, modified by cold-heat-deficiency-repletion and concurrent patterns into a system' evolution makes Siwu the pivot for understanding the whole 'blood-pattern treatment' and blood-tonifying compatibility — truly the 'ancestor of blood formulas.' It is now widely used across gynecology, dermatology (blood-deficiency wind-dryness skin conditions), and internal medicine for constructive-blood deficiency-and-stagnation.

Active constituents: from ferulic acid and paeoniflorin to antioxidant exploration

In modern terms, the material basis involves each herb's actives: angelica's ferulic acid, ligustilide, and polysaccharides, chuanxiong's tetramethylpyrazine and ferulic acid, white peony's paeoniflorin, and rehmannia's catalpol and polysaccharides. Pharmacology reports hematopoiesis-promoting, antioxidant, immunomodulatory, microcirculation-improving, and estrogen-like activities. An experimental study (2014), for example, showed Siwu activating Nrf2-mediated detoxifying/antioxidant genes and reducing oxidative damage, and a network-pharmacology study on cancer-related anemia (2023) sketched a multi-target 'hematopoiesis-promoting' mechanism hypothesis.

A post-hoc analysis of a Taiwan randomized double-blind placebo-controlled trial further examined Siwu's effects on anemia-related hemogram parameters (for 'nourishing blood') and the uterine-artery pulsatility index (for 'blood stagnation'), attempting to read the traditional 'nourish-and-invigorate-blood' meaning in modern measures. The caveat: these are largely in-vitro, animal, computational, and exploratory — mechanistic exploration, and the modern findings of 'promoting hematopoiesis/antioxidant' cannot be equated with proven efficacy in human disease (especially 'treating anemia').

Evidence: what primary-dysmenorrhea research shows

Siwu and its relatives have relatively more clinical research in primary dysmenorrhea. A systematic review and meta-analysis in Maturitas (2020) assessed randomized controlled trials of Siwu for primary dysmenorrhea; as early as 2007, a Taipei randomized double-blind placebo-controlled pilot trial (76 young women) assessed its efficacy and safety for primary dysmenorrhea by Western methodology. There is also a systematic review and meta-analysis of Taohong Siwu Tang for primary dysmenorrhea (PMID 32723605).

How to state it? First, a substantial share of studies used modified formulas such as Taohong Siwu Tang rather than the canonical Siwu, which must not be conflated. Second, included studies vary in sample size and methodological quality, some are pilot/exploratory, and heterogeneity needs attention. Third, outcomes are mostly specific measures such as dysmenorrhea pain scores. The defensible statement is that Siwu and its relatives (especially Taohong Siwu Tang) show a randomized-controlled signal of improving pain in primary dysmenorrhea, but with variable evidence quality, partly from modified formulas, needing high-quality RCT confirmation — not that Siwu is proven to treat dysmenorrhea. The cause of dysmenorrhea (primary vs secondary) must first be assessed by gynecology.

Quality standards, patent medicines, and the Western-drug context

Prepared rehmannia, angelica, white peony, and chuanxiong are all Chinese Pharmacopoeia (2020) materials (angelica by ferulic acid, white peony by paeoniflorin, chuanxiong by ferulic acid). The market offers Siwu mixture, granule, and paste, and many patent medicines built on the Siwu base (compounds such as Bazhen Yimu and Wuji Baifeng lines often contain Siwu components); same-named forms and modified formulas differ markedly in ratio and are not equivalent. Blood-heat types often substitute raw rehmannia/red peony, so which herb is used should be noted.

As contextual overlap (relationship only, not an efficacy comparison): the formula's modern research settings (blood deficiency, irregular menses, primary dysmenorrhea, anemia) may be adjacent to Western-drug categories such as blood-building drugs like iron, NSAIDs (dysmenorrhea analgesia), and hormonal menstrual regulators — this is adjacency of application only, never equivalence of constituents or efficacy (especially 'nourish blood' is not 'iron supplementation for anemia'). Also, angelica and chuanxiong have some blood-moving action, so combining with anticoagulant/antiplatelet drugs may increase bleeding tendency, and combination requires professional assessment.

Safety boundaries: cloying burden, blood-moving, and caution in pregnancy

Although a mild blood-nourishing formula, Siwu has boundaries. First, cloying burden: rehmannia is cloying, so weak digestion, poor appetite with loose stool, or damp-exuberance fullness are unsuited or need pairing with spleen-fortifying, qi-regulating agents, and prolonged use may burden the stomach. Second, blood-moving: angelica and chuanxiong invigorate blood, so heavy menstrual flow, a bleeding tendency, or co-use with anticoagulant/antiplatelet drugs need caution, as bleeding may increase. Third, caution in pregnancy: although history includes adding gelatin-mugwort for fetal stirring, Siwu contains blood-movers, so pregnant women (especially with threatened miscarriage or bleeding) should use it under medical guidance. Yin-deficiency fever and reckless blood-heat need corresponding adjustment (such as substituting raw rehmannia and red peony).

On the boundary of use: irregular menses, dysmenorrhea, a sallow complexion, and dizziness have many causes: anemia must have its type and cause established (iron deficiency, blood loss, nutrition, chronic disease) and be treated accordingly; dysmenorrhea must first have secondary causes such as endometriosis excluded by gynecology; abnormal uterine bleeding especially requires prompt care. It should not be self-taken long-term merely to 'nourish blood.' Siwu is an excellent model for the wisdom of blood-nourishing and blood-regulating compatibility, but its clinical use belongs to professional differentiation.

A checklist for reading any formula article

1. Composition and preparation: does a stated effect come from the canonical Siwu, or from Taohong Siwu, Bazhen, or Shengyu? Is raw rehmannia/red peony substituted (blood-heat type)? These must not be conflated.
2. Pattern versus disease: has 'blood-deficiency pattern' been equated directly with the modern 'anemia,' and has 'blood-deficiency is not anemia' and the 'belonging to constructive-blood deficiency-and-stagnation' qualifier been dropped?
3. Evidence tier and scenario: does the positive result use the canonical Siwu or a modified formula like Taohong Siwu, and human RCTs or animal/network-pharmacology work — with what quality and heterogeneity?
4. Safety and interactions: does it address rehmannia's cloying burden, angelica/chuanxiong blood-moving (bleeding tendency/anticoagulant interaction), caution in pregnancy, and adjustment for blood-heat?
5. Dose and procedure: responsible education identifies the entity and stops short of individual dosing and modifications — for menstrual abnormalities, anemia, or dysmenorrhea, first seek a cause diagnosis, and consult a physician and pharmacist for prescriptions.

Educational and academic reference only. It does not provide a diagnosis, prescription, dosage, or treatment recommendation. A 'blood-deficiency pattern' is not the modern 'anemia'; rehmannia is cloying and burdens the stomach, and angelica and chuanxiong move blood and may increase bleeding when combined with anticoagulants — use with caution in pregnancy. Menstrual abnormalities, anemia, or dysmenorrhea should first be medically evaluated for cause; consult a licensed physician and pharmacist for any prescription.