Stems and woodsBlood-activatingSappan Lignum

Su Mu (Sappan Wood)

Q: What is Sumu? Is it the same as Honghua or Taoren?

Sumu is the dried heartwood of Caesalpinia sappan, also referred to as Sappan Lignum. It is used to activate blood, expel stasis, reduce swelling, and relieve pain. Honghua and Taoren have different primary actions and cannot be used interchangeably in equal amounts; pregnancy requires caution.

Q: What are the composition and effects of Sumu?

Sumu is the pharmacopoeial name for Caesalpinia sappan L. It is sweet and salty in taste, neutral in nature, enters the Heart, Liver, and Spleen meridians, and functions to activate blood, expel stasis, reduce swelling, and relieve pain. It is used for traumatic injuries, fractures and sinew injuries, blood-stasis swelling and pain, amenorrhea and dysmenorrhea, postpartum stasis obstruction, chest and abdominal stabbing pain, and abscesses.

Q: What is the dosage of Sumu? Can it be used daily as a blood-activating tea?

The decoction dosage is 3–9 g, but modern use requires physician-determined dosage. It is not meant to be used year-round as a "Sumu tea," and prolonged use may further harm pregnancy. Traumatic injuries require short-term, physician-guided use and cannot be treated by self-dosing.

Q: What are the contraindications of Sumu? Can pregnant women use it?

Sumu is not suitable for pregnant women. People with blood deficiency without stasis or with excessive menstruation need physician evaluation. If bloody stools or abdominal pain occur, stop using it. Severe fractures or high fever require immediate medical care.

Q: Can Sumu activate blood, reduce swelling, and relieve pain?

Yes. It can assist in traumatic injuries, fractures and sinew injuries, blood-stasis swelling and pain, amenorrhea and dysmenorrhea, postpartum stasis obstruction, chest and abdominal stabbing pain, and abscesses. It activates blood and expels stasis, and reduces swelling and relieves pain, but it is not a specific remedy for every injury or every case of dysmenorrhea.

Q: Can Sumu be taken daily as a blood-activating or pain-relieving tea?

It may be used short-term in formulas for blood-stasis injuries, but prolonged use can further injure pregnancy. The idea that Sumu must always activate blood is not a substitute for evaluation, and blood-activating or swelling-reducing use should be based on physician-determined formulation and dosage.

Q: How to choose between Sumu, Honghua, Taoren, Danshen, and Chuanxiong?

Sumu is used to activate blood and reduce swelling, especially for traumatic injuries. Honghua activates blood and unblocks meridians; Taoren activates blood and moistens the intestines; Danshen activates blood and expels stasis; and Chuanxiong activates blood and moves qi. Pattern differentiation applies, and large doses of Sumu are contraindicated in pregnancy.

A practical guide to Su Mu: what it is, how Traditional Chinese Medicine uses it, the classical formulas it appears in, and who should be careful with it.

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Last reviewed Oct 29, 2026

Quick Facts

Latin Name	Sappan Lignum
Chinese Name & Pinyin	蘇木 · Su Mu
Medicinal Part	Stems and woods
The item	Su Mu is the dried heartwood of sappanwood, reddish-brown with clear growth rings. Tao Ren is not this drug. It usually goes into decoctions, or the warm decoction is used externally as a wash.
Nature and channels	Sweet, salty, acrid, neutral. Enters the Heart and Liver. Sweet salty acrid neutral moves stasis, frees the vessels, and harmonizes qi and blood.
Pharmacopoeia line	Dispels stasis and harmonizes the blood. Used for bruising and swelling after falls and sprains, postpartum blood-stasis abdominal pain and lochia not flowing, and tight, uncomfortable limbs and joints.
Pattern cues	Bruised swollen limbs. Postpartum abdominal pain. Tight joints. Dull complexion with local dark pigment.
In this article	Su Mu versus Tao Ren. Moving limb stasis versus moving internal stasis. Why pregnancy is forbidden. Why injury and postpartum pain need a clinic. Who should skip it.

What Is Su Mu?

Su Mu (苏木; Sū Mù; Latin: Sappan Lignum; English: sappanwood) in the current pharmacopoeia is the dried heartwood of the small tree Caesalpinia sappan of the pea family, cut in autumn and winter and split into pieces or thin slices. It is sweet, salty, acrid, and neutral, enters the Heart and Liver channels, and its core actions are to move and disperse stasis stagnation, and to harmonize the qi and blood. It usually goes into decoctions. The usual amount is 3–9 g. It needs no special decocting order. External use is a suitable amount of the warm decoction as a wash or compress for bruised, swollen spots.

It is not Tao Ren. Peach kernel is neutral with bitter and sweet flavors, slightly moistening, and leans to dispersing the stasis blood of the internal viscera — the intestines and uterus — while also moistening the intestines. Su Mu is gentler, leaning to the stasis of the limbs and joints. Use caution in pregnancy — in fact it is forbidden in pregnancy. Heavy periods is a poor match. Deficiency without stasis, with fatigue, shortness of breath, and a pale face, gets worse if it is added. Sprains, fractures, and postpartum stasis pain need a clinic first. Do not keep increasing it on your own.

It is used most often for three patterns:

Falls and sprains — bruised, swollen, painful limbs — seek care
Postpartum blood-stasis abdominal pain, lochia not flowing smoothly — seek care
Tight, uncomfortable limbs and joints; dull complexion from qi-blood disharmony

Sweet, salty, acrid, and neutral, it is not a daily “circulation wood” to keep increasing. Moving stasis when there is no stasis, in a deficient body, consumes the upright qi and blood.

When a fall twists a limb and blood leaves the vessels, or postpartum stasis blocks the uterus, bruising, swelling, and fixed abdominal pain are common. Su Mu is sweet, salty, acrid, and neutral. It moves stasis and harmonizes the qi and blood, which is why it appears in Su Mu Tang (Sappanwood Decoction)–type formulas, paired with Dang Gui and Hong Hua. It frees more than it holds. Deficiency without stasis, with fatigue and a pale face, gets worse if more is added.

Su Mu is not a catch-all circulation or bruising wood. In deficiency without stasis, with no blood blockage, or in pregnancy, using it alone is a poor match. Decoction or compress, and whether it belongs in a formula, should be decided by a licensed Chinese medicine practitioner after pattern diagnosis.

Su Mu: Materia Medica Profile

Identification & Quality Standard

Sappan Lignum

Botanical Origin

The cried heartwood of Caesalpinia sappan L.(Fabaceae)

Production Regions

Primarily produced in the Chinese provinces of Guizhou, Guangdong, Guangxi, Taiwan.

Quality Requirements

Superior medicinal material is firm, thick, large, yellowish-red.

Macroscopic Features

Long cylindrical or half-cylindrical shape, 10~100cm long, 3~12cm diameter. Externally yellowish-red to dark red, alternating red and white thin striations, with scars of knife cuts and scars of stems, often with longitudinal cracks. Fractured surface is slightly lustrous, obvious annual rings; sometimes has pith that is dark brown and loose with bright spots. Hard texture, faint odor, slightly astringent taste.

Main Regions and Quality Identification

Traditional materia medica and industry experience value the Su Mu of certain producing areas — including several provinces of southwestern China — but actual quality also depends on variety, harvest time, processing, and storage. In appearance, good-quality Su Mu slices are long-cylindrical or irregular thin pieces, reddish-brown or yellowish-brown on the surface, with clear growth-ring texture, hard texture, a shiny cross-section, a faint fragrance, and a slightly astringent taste. The common look-alikes are other similarly colored woods — some of the red hardwoods — with looser texture, less shiny cross-sections, and weaker odor — distinguish them carefully when buying.

Traditional Properties & Historical Lineage

Nature, Flavour & Channel Tropism

Sweet, Salty; NeutralHeartLiverSpleen

1. Records in Classic Materia Medica

Ming Yi Bie Lu: mentions that Su Mu governs breaking blood, and treats postpartum blood-distension and abdominal pain.
Xin Xiu Ben Cao: supplements that it can disperse carbuncle swelling and harmonize the qi and blood.
Ben Cao Gang Mu: records that it treats deficiency-consumption, stasis stagnation, and women's qi-blood heart and abdominal pain.

These records all center on its stasis-moving, dispersing action — none touches the specific conclusions of modern medicine.

2. How Views of Its Nature Changed

Views among physicians differ to a degree: some lean to its stasis-moving, dispersing action — mostly for the excess patterns of falls and injuries and postpartum stasis; some hold its nature gentle, usable for some mild-to-moderate qi-blood disharmony, but stress that it should not be used for the deficiency without stasis, to avoid wasting the upright qi; some note its action on the tight, uncomfortable limbs and joints, using it as an adjuvant for joint discomfort. These different views gradually clarified its range of use — and also kept it from being treated as a wonder drug.

Core Efficacies & Traditional Applications

Traditional Functions

Invigorates blood and dispels stasis, reduces swelling and relieves pain.

1. First Direction: Moving and Dispersing Stasis

Traditional action: move and disperse the qi-blood stasis, helping restore the normal flow of qi and blood.
Typical signs: local bruising, swelling, and pain after falls and injuries; the abdominal distension and pain of women in the postpartum period from stasis stagnation; and the tight, uncomfortable limbs and joints from qi-blood stasis.
Usual combinations: for falls and injuries, often paired with Ru Xiang and Mo Yao — strengthening the stasis-moving, pain-stopping action; for postpartum stasis, often paired with Dang Gui and Chuan Xiong — attending to nourishing the blood while moving and dispersing.
Who should not self-use: those without a clear stasis presentation should not self-use, to avoid wasting the upright qi.

2. Second Direction: Harmonizing the Qi and Blood

Traditional action: harmonize the qi and blood, helping improve the whole-body discomfort of qi-blood disharmony.
Typical signs: a dull complexion, local skin pigment spots, and the emotional tightness and chest oppression of qi-blood disharmony.
Usual combinations: often paired with the qi-regulating herbs — such as Xiang Fu and Chen Pi — because when the qi moves, the blood moves; regulating the qi helps harmonize the qi and blood better.
Who should not self-use: those with qi-blood deficiency as the main state — otherwise the qi-blood insufficiency may worsen.

3. Classic Pairing: Su Mu With Dang Gui

The common pair is Su Mu with Dang Gui: Dang Gui is good at nourishing and harmonizing the blood; Su Mu is good at moving and dispersing stasis. Combined, Dang Gui restrains the overly drastic moving-dispersing nature of Su Mu, avoiding the wasting of blood, while Su Mu strengthens Dang Gui's stasis-moving action — nourishing the blood without leaving blockage. This pair mainly fits the patterns of both qi-blood insufficiency and mild stasis — such as mild uncleared postpartum stasis with qi-blood deficiency — and the bruise-and-swelling cases after injury in those of a weaker constitution. But it needs the physician's pattern diagnosis — do not pair and take on your own.

Modern Research

Modern research offers useful context, but Traditional Chinese Medicine prescribes on whole-pattern diagnosis rather than isolated compounds.

1. Main Chemical Constituents

The main constituents detected in Su Mu are flavonoid compounds, plus small amounts of volatile oils and tannins. These constituents are naturally present in the plant. In in vitro experiments, some flavonoid constituents show a certain antioxidant action; in animal experiments, some studies show the Su Mu extract may have a certain effect on improving local circulation — but these results cannot be directly equated with the effect after taking it in humans; currently, no sufficient human clinical research has reached a clear conclusion.

2. Current Research Directions

Current research mainly focuses on the activity observation of the flavonoid constituents in Su Mu, and the possible effect on local circulation:

Some flavonoid constituents show a certain antioxidant activity in in vitro experiments.
The extract may influence local circulation in animal models.

More human research is still needed to verify whether these actions can be realized in the human body.

3. Limitations of Current Research

Lab results are not clinical efficacy — in vitro and animal results cannot be directly extended to humans.
Extracts and monomers are not the same as traditional slices — the human body takes the processed and combined slices, not the extract of a single constituent.
Doses and preparation methods vary between studies — the results are hard to unify.
A single component does not define the whole herb — Chinese herbs act through the joint work of many constituents — a single constituent's activity cannot represent the whole herb's action.

Comparing Similar Herbs

1. What They Share

Choosing the similar herb Tao Ren, the two share these points:

Both have the action of moving and dispersing stasis.
Both can be used for the traditional qi-blood stasis patterns — falls and injuries, and postpartum stasis.
Both need the constitution and dose considered — neither should be used casually.

2. The Key Differences: Su Mu vs. Tao Ren

Nature and flavors: Su Mu is neutral with sweet, salty, and acrid flavors — neither cold nor hot; Tao Ren is neutral-leaning with bitter and sweet flavors — slightly moistening.
Focus: Su Mu leans to moving and dispersing the stasis of the limbs and joints while harmonizing the qi and blood — attending to both the flow and the harmonization; Tao Ren leans to moving and dispersing the stasis of the internal viscera — such as the stasis blood in the intestines and uterus — with a certain intestine-moistening, stool-freeing action.
Qi tendency: Su Mu's moving-dispersing action is relatively gentle — mainly acting on the qi of the body surface and limbs — freeing but not drastic; Tao Ren's moving-dispersing action is relatively stronger — leaning to the internal viscera — with a moistening-descending character.
Best fit: Su Mu fits the limb bruising and swelling after falls, the joint tightness, and the mild postpartum abdominal distension; Tao Ren fits the heavier postpartum stasis abdominal stabbing pain, and constipation with stasis.
Not suitable: Su Mu — not for the deficiency-without-stasis or pregnancy; Tao Ren — likewise not for pregnancy, and because of the moistening action, those with spleen-deficiency diarrhea also need caution.
Use scenes: Su Mu often appears in the formulas regulating limb bruising and joint discomfort, and can also be used in light food-therapy regulation; Tao Ren often appears in the formulas regulating internal viscera stasis blood — such as the intestine-moistening or gynecological-regulating formulas — rarely in daily food therapy.

3. One-Sentence Summary

Simply put, Su Mu leans toward moving and dispersing the stasis of the limbs and joints and harmonizing the qi and blood, whereas Tao Ren leans toward moving and dispersing the stasis blood of the internal viscera and moistening the intestines. Both can be used for qi-blood stasis, but they are not interchangeable.

Classical Formulas Containing Su Mu

Classic Formula 1: Ba Wei Shun Qi San (Eight-Ingredient Qi-Soothing Powder)

Combination logic: In this formula, Su Mu is an auxiliary — the assistant — mainly assisting the moving and dispersing of qi-blood stasis, helping the qi-regulating herbs work better. The lords are the qi-regulating herbs Wu Yao and Qing Pi; the ministers are the spleen-strengthening herbs Bai Zhu and Fu Ling. Su Mu works with the qi-regulating and spleen-strengthening to regulate the qi and qi-blood together. Su Mu alone cannot be used, because alone it cannot attend to the overall qi-regulating and spleen-strengthening, nor reach the effect of regulating the blocked qi.

Traditional use: traditionally for the qi-blood stasis of blocked qi movement — chest oppression, abdominal distension and pain, and heavy limbs.

Modern note: modern clinical use of this formula requires the doctor's pattern diagnosis and standard care — do not self-apply just because the formula name relates to a certain disease — the physician must adjust the herbs to the specific condition.

Classic Formula 2: Su Mu Tang (Sappanwood Decoction)

Combination logic: In this formula, Su Mu is the lord — the main stasis-moving, dispersing herb — paired with the blood-nourishing, stasis-moving herbs Hong Hua and Dang Gui, jointly targeting the postpartum stasis stagnation. The other herbs in the formula help harmonize the qi and blood, keeping the moving-dispersing from being too drastic. Su Mu alone cannot attend to the blood-nourishing and qi-blood harmonizing — hard to relieve the postpartum abdominal distension and pain and the stasis stagnation.

Traditional use: traditionally for the female postpartum abdominal pain of uncleared stasis and unsmooth lochia.

Modern note: modern clinical use likewise requires the doctor's pattern diagnosis — especially the special postpartum body state — do not take it on your own.

Formulas vs. Single Herbs

A formula is the whole of many herbs working together — each herb has a specific place and role in the formula; a single herb cannot simply replicate a full formula's effect. The doses and combinations in a formula are holistic — the pairing of different herbs restrains and reinforces one another, reaching a better regulating effect. The common misunderstanding: a herb that works in a formula does not mean taking it alone produces the same effect — a single herb's action is limited and cannot replace the whole regulation of a formula — so do not build formulas from online articles.

Diet & Daily Home Use

1. Home Tea

Su Mu Rose Tea: Su Mu slices 3 g, Mei Gui Hua 2 g, Da Zao 1 piece (pitted). Steep all the materials in boiling water, cover 10 minutes, and drink; can be re-steeped until the flavor fades. Suited to the mild qi-blood disharmony — a dull complexion, occasional mild limb tightness, or the light regulation of emotional tightness. Not for pregnant women, women with heavy menstrual flow, or the deficiency-without-stasis. Suggested: 1–2 times a week; not for long-term continuous drinking. Note: Su Mu is a medicinal slice — do not use it casually as an ordinary food; strictly control the amount to avoid excess.

2. Decoction and Processing Differences

The difference between the raw and processed Su Mu mainly lies in texture and decoction effect: the raw is harder, and cutting helps release the effective constituents; the processed has a slightly faster release after simple handling — but the overall efficacy differs little. For home decoction, Su Mu needs no pre-boiling, late addition, or bag-boiling — decoct it directly with the other food or herbs; for tea, steep it directly. Different forms cannot be converted directly — the slice dose and the tea amount differ — do not replace by simple ratio, and do not use tea to replace medicinal decoction.

3. Dosage and Course

The common dose in traditional prescriptions is 3–9 g — the dose should not be too large for regulation. The food-therapy dose should be smaller — for example, about 3 g in tea — and should not be confused with the medicinal dose. Long-term continuous use is not advised — continuous use should preferably not exceed 1 week; if long-term regulation is needed, consult a physician or pharmacist to adjust the plan per the constitution, avoiding the wasting of upright qi from long-term use.

Contraindications & Safety Warnings

1. Who Should Avoid It

The deficiency without a clear stasis presentation — such as those who often feel fatigued, short of breath, or pale — should not use it.
Pregnancy and breastfeeding — no sufficient safety basis currently — avoid use.
Children and the elderly — special constitutions — consult a physician before use.
Liver or kidney impairment — use with caution, to avoid adding burden to the body.
Allergy to Fabaceae plants — may be allergic to Su Mu — avoid use.
Those in special treatment — such as anticoagulation or gynecological treatment — consult a doctor first.

2. Interactions and Diet Notes

There is no sufficient evidence that Su Mu "clashes" with ordinary foods, but certain herbs can interact with specific drugs: those taking anticoagulant medications should consult a doctor before use, to avoid affecting the drug effect; those taking blood-pressure or glucose-lowering medications should also inform the physician that they are using Su Mu, to avoid potential interactions. There is no sufficient evidence of a general "food clash" between ordinary foods, but certain herbs can interact with specific drugs — those on medication should consult a doctor or pharmacist first.

3. Adverse Reactions and Overdose Risk

Overdosing on Su Mu may cause gastrointestinal discomfort — nausea, vomiting, and abdominal discomfort — and may also bring dizziness and fatigue. If marked discomfort, allergy signs (such as rash or itching), persistent vomiting, breathing difficulty, altered consciousness, or rapidly worsening symptoms appear, stop at once and seek medical care — do not delay the illness.

Frequently Asked Questions About Su Mu

What is Sumu? Is it the same as Honghua or Taoren?

Sumu is the dried heartwood of Caesalpinia sappan, Latin name Sappan Lignum. It is a common Chinese medicine centered on activating blood and expelling stasis, and reducing swelling and relieving pain. Honghua activates blood and unblocks meridians. Taoren activates blood and expels stasis while moistening the intestines. They cannot be used interchangeably in equal amounts. Prescribe as Sumu. Caution in pregnancy.

What are the composition and effects of Sumu?

Pharmacopoeial name Sumu, Latin Caesalpinia sappan L. Sweet and salty in taste, neutral in nature, enters the Heart, Liver and Spleen meridians. Functions to activate blood and expel stasis, and reduce swelling and relieve pain. Used for traumatic injuries, fractures and sinew injuries, blood-stasis swelling and pain, amenorrhea and dysmenorrhea, postpartum stasis obstruction, chest and abdominal stabbing pain, and abscesses. Activates blood and reduces swelling.

How to choose between raw and processed? Can Honghua replace it?

Heartwood is used raw. Honghua emphasizes unblocking meridians rather than strongly reducing swelling, and cannot replace it in equal amounts. Commercial products are standardized; do not adjust arbitrarily.

What is the dosage of Sumu? Can it be used daily as a blood-activating tea?

Decoction, 3-9g. Modern use requires physician-determined dosage. It is not a year-round "Sumu tea." Pregnancy will be further injured by prolonged use. Traumatic injuries require short-term, physician-determined dosage and cannot replace evaluation.

What are the contraindications of Sumu? Can pregnant women use it?

Not suitable for pregnant women. Blood deficiency without stasis or excessive menstruation requires physician evaluation. Stop if bloody stools or abdominal pain occur. Seek immediate medical care for severe fractures or high fever.

Can Sumu activate blood, reduce swelling, and relieve pain?

It can assist traumatic injuries, fractures and sinew injuries, blood-stasis swelling and pain, amenorrhea and dysmenorrhea, postpartum stasis obstruction, chest and abdominal stabbing pain, and abscesses. It activates blood and expels stasis, and reduces swelling and relieves pain, but is not a specific remedy for all injuries or all dysmenorrhea.

Can Sumu be taken daily as a blood-activating or pain-relieving tea?

Blood-stasis injuries can be used short-term in formulas; pregnancy will be further injured. The idea that "Sumu must activate blood" cannot replace evaluation. Activating blood and reducing swelling requires physician-determined formulation and dosage.

How to choose between Sumu, Honghua, Taoren, Danshen, and Chuanxiong?

Sumu activates blood and reduces swelling, suited to traumatic injuries. Honghua activates blood and unblocks meridians. Taoren activates blood and moistens the intestines. Danshen activates blood and expels stasis. Chuanxiong activates blood and moves qi. Choose Sumu for activating blood; Honghua for unblocking meridians; Taoren for moistening the intestines; Danshen for expelling stasis; Chuanxiong for moving qi. Pattern differentiation applies, but large doses of Sumu are contraindicated in pregnancy.

How is Sumu commonly modified? What is a representative usage?

Modifications depend on the pattern. Add Honghua for traumatic injuries; add Taoren for dysmenorrhea. Specify Sumu; do not substitute Honghua in equal amounts for reducing swelling.

How to select and store Sumu?

Choose regular Chinese medicinal materials with intact heartwood. Discard if moldy, damp, or abnormal in odor. Store in a dry place. Purchase "Sumu"; do not substitute Honghua or Taoren in equal amounts for activating blood, reducing swelling, and relieving pain.

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Medical Disclaimer — This article is provided for educational purposes only and describes traditional Chinese medicine concepts. It is not medical advice, and it is not intended to diagnose, treat, cure or prevent any disease. Always consult a qualified practitioner before using any herb, particularly if you are pregnant, nursing, taking medication or managing a diagnosed condition.