Su Mu (苏木) — Sappanwood: TCM Uses, Trauma Treatment & Formulas

At a Glance

• Herb: Su Mu
• Chinese name: 苏木 (Sū Mù)
• Latin name: Caesalpinia sappan heartwood
• Nature: Neutral
• Taste: Sweet / Salty
• Meridian: Heart / Liver / Spleen
• Category: Herbs that Invigorate Blood and Resolve Stasis
• Introduction: Su Mu (苏木), the dried heartwood of Caesalpinia sappan L. (sappanwood), is an ancient blood-activating herb and natural dye plant whose bright red color from brazilin and brazilein pigments serves both medicinal and practical purposes. Recorded in the Xin Xiu Ben Cao of the Tang dynasty, it is used for blood stasis conditions in traumatology, gynecology, and cardiovascular medicine. Modern pharmacology has confirmed brazilin, sappanin, and homoisoflavonoids with anti-platelet, anti-inflammatory, immunosuppressive, antitumor, and cardioprotective activities, with brazilin showing particular promise for cardiovascular and metabolic diseases.

Action

• Activates blood and dispels stasis — treats traumatic injury, postpartum stasis, and menstrual disorders
• Reduces swelling and relieves pain — addresses swelling and pain from blood stasis
• Unblocks the channels — treats bi syndrome with blood stasis
• Calms the heart (secondary) — used in some classical texts for heart palpitations from stasis

Clinical Application

• Traumatic injury with bruising, swelling, and pain
• Postpartum blood stasis: lochia retention, abdominal pain with masses
• Dysmenorrhea and amenorrhea from blood stasis
• Chest pain and angina from blood stasis in the heart vessels
• Bi syndrome with blood stasis and joint pain

Precautions

• Standard dose: 3–9 g
• Contraindicated in pregnancy — activates blood and may cause miscarriage
• Contraindicated in blood deficiency without stasis
• Use with caution in patients on anticoagulants — additive anti-platelet effect
• The red decoction color is normal and due to brazilin pigment

Formula

• Combined with Hong Hua, Tao Ren, Dang Gui for amenorrhea and dysmenorrhea from blood stasis
• Combined with Ru Xiang, Mo Yao, San Qi for traumatic injury with swelling and pain
• Tong Jing Wan (通经丸): Su Mu, Hong Hua, Dang Gui, Tao Ren, Chuan Xiong — activates blood and unblocks menstruation for amenorrhea
• Combined with Dan Shen, Chuan Xiong, San Qi for angina and coronary artery disease

Combinations

• 乳香 (Rǔ Xiāng) + 没药 (Mò Yào) — traumatic injuries with swelling, pain, and stasis. 2. 当归 (Dāng Guī) + 川芎 (Chuān Xiōng) — amenorrhea and dysmenorrhea from blood stasis. 3. 红花 (Hóng Huā) + 桃仁 (Táo Rén) — postpartum blood stasis with abdominal pain. 4. 大黄 (Dà Huáng) — constipation combined with blood stasis from trauma. 5. 土鳖虫 (Tǔ Biē Chóng) + 自然铜 (Zì Rán Tóng) — fractures and bone injuries. Source: 本草纲目, 医学启源.

Pharmacological Effects

• brazilein
  • Anti-inflammatory: inhibits NF-κB, COX-2, and iNOS
  • Anti-inflammatory: reduces paw edema comparable to indomethacin
  • Immunosuppressive: suppresses T-cell proliferation and Th1/Th17 cytokine production — potential in autoimmune conditions
  • Neuroprotective: reduces β-amyloid aggregation and tau hyperphosphorylation in AD models
• brazilin
  • Anticoagulant: inhibits thrombin-induced platelet aggregation
  • Anticoagulant: prolongs activated partial thromboplastin time
• Antimicrobial
  • brazilin active against MRSA and vancomycin-resistant Enterococcus
• sappanin A
  • Anticancer: induces apoptosis in colorectal and gastric cancer lines via caspase-3/9 activation

Classic Description

• Ben Cao Gang Mu (《本草纲目》): ‘Sappan Wood is an herb of the three yin channel blood aspect; used in small amounts it harmonizes blood, used in large amounts it breaks blood.’
• Tang Ben Cao (《唐本草》): ‘Governs breaking blood; for postpartum blood distension and oppression about to cause death — decoct five liang in water, extract the thick juice and take orally.’
• Ben Cao Bei Yao (《本草备要》): ‘Activates blood and expels stasis, disperses swelling and settles pain; treats traumatic injury, carbuncles and abscesses, postpartum blood collapse, breaks dead blood, and expels postpartum lochia.’