Sophora Flavescens (Ku Shen): Evidence-Based Anti-Inflammatory Root for Eczema and Psoriasis (2026)

By Ava Huang, Herbal Science Researcher at QICAOGANGMU | Updated: May 2026 | Reading time: 12 minutes

Sophora flavescens, known in Traditional Chinese Medicine as Ku Shen (苦参, "bitter root"), is one of the most extensively studied herbs in modern dermatological research. For centuries it has been used to "clear Heat," "dry Dampness," "expel Wind," and "stop itching" - properties that now have concrete pharmacological explanations. This deep-dive covers every major published mechanism of Ku Shen's action on eczema, psoriasis, and sensitive skin, with inline PubMed citations for each claim.

Ku Shen is the primary anti-inflammatory herb in QICAOGANGMU Caoben Yijun Rugao at a 1.5% concentration. Understanding its mechanisms helps explain why the formula works and why independent third-party evidence supports it.

Quick reference: Sophora flavescens (Ku Shen) for skin conditions

Ku Shen in Traditional Chinese Medicine

Ku Shen is categorised in TCM by its bitter taste and cold nature. Its primary actions map precisely onto the mechanisms now confirmed by modern pharmacology:

• Clears Damp-Heat - addresses skin conditions that are red, swollen, hot, itchy, and may involve oozing. Corresponds to NF-kB driven cytokine cascades.
• Expels Wind and stops itching - targets histamine-independent itch pathways (the "Wind" driving neurogenic itch).
• Kills parasites / antimicrobial - the antibacterial and antifungal activity now confirmed for MRSA and Trichophyton species.
• Detoxifies - corresponds to suppression of pro-inflammatory cytokines including TSLP, TNF-alpha, and IL-1beta.

In TCM, Ku Shen is frequently combined with Cnidii Fructus (She Chuang Zi) for skin disorders - a pairing that modern research has confirmed produces synergistic antipruritic effects greater than either herb alone. PMC6151778

Anti-inflammatory actions: the full pharmacological picture

NF-kB pathway inhibition

The central anti-inflammatory mechanism. Sophoraflavanone G and kushenol F from Ku Shen powerfully suppress pro-inflammatory cytokines IL-6, IL-8, CXCL1, TNF-alpha, and IL-1beta. PMID 38358770. Studies show these compounds reduce psoriasiform inflammation comparably to conventional topical steroids in cellular models - but through an immunomodulating rather than immunosuppressing mechanism. This is the critical distinction: NF-kB modulation reduces the inflammatory response while preserving the immune system's ability to fight infection, which is why Ku Shen does not worsen fungal infections the way steroids do.

Multi-pathway STAT3 and AKT1 inhibition

Matrine from Ku Shen significantly improved DNCB-induced eczema in mouse models, reducing TNF-alpha and IL-4, and suppressing STAT3, TP53, and AKT1 signalling pathways - key drivers of chronic atopic dermatitis. PMID 36216196

Synergistic effects with Angelica sinensis

The Sophora flavescens - Angelica sinensis pairing (found in classical TCM formulas) alleviates eczema by inhibiting TLR4/MyD88/NF-kB signalling in mice, with co-extracted preparations showing potent suppression of NF-kB, IL-1beta, TNF-alpha, iNOS, and COX-2. PMID 38154523, PMID 21976127

Antipruritic (itch-relief) actions

Histamine-independent itch suppression

Sophora flavescens extracts demonstrate strong antipruritic effects, significantly reducing both acute and chronic itch-related responses in animal models. PMID 12736520. This is clinically important: eczema itch is predominantly non-histaminergic - it is driven by cytokines and neurogenic pathways that antihistamines cannot address. Ku Shen works on these histamine-independent pathways.

TSLP suppression - blocking the itch trigger at source

Kushenol F, a flavanonol from Sophora flavescens, suppresses TSLP (thymic stromal lymphopoietin) production in atopic dermatitis models. PMID 36355519. TSLP is a key cytokine that drives the intense itch characteristic of eczema - it activates itch neurons directly. By reducing TSLP at the cellular level, kushenol F addresses itch at its source rather than at the nerve ending.

Neutrophil extracellular traps (NETs) - an emerging mechanism

Formononetin, a compound from Sophora flavescens, alleviates atopic dermatitis by suppressing neutrophil extracellular traps via PAD4/MPO inhibition. PMID 40635516. NETs are a newly identified driver of atopic dermatitis skin inflammation, and this represents a mechanistic pathway not addressed by any conventional topical treatment.

Antiproliferative action for psoriasis

Psoriasis is characterised by keratinocyte hyperproliferation - skin cells dividing far faster than normal, producing the thick scaly plaques. Oxymatrine significantly inhibits keratinocyte proliferation, and a clinical study in psoriasis patients showed significant improvement in PASI scores with oxymatrine treatment. PMID 28450041

A systematic review of topical herbal formulae for psoriasis - including those containing Sophora flavescens root - confirmed improvement in psoriasis outcomes via anti-inflammatory, antiproliferative, and tissue-repair mechanisms. PMID 23817996. An in vivo study using enhanced topical delivery of Sophora flavescens in mouse models showed further improvement in psoriasis outcomes with optimised delivery. Zeng J et al. 2025, Journal of Traditional Chinese Medical Sciences

Antibacterial and skin barrier effects

MRSA activity - clinically relevant for eczema

Sophoraflavanone G from Sophora flavescens exhibits significant antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) by disrupting bacterial membrane integrity and inhibiting biofilm formation. PMID 38358770. Staph aureus colonises over 90% of eczema-affected skin and directly amplifies the cytokine cascade, worsening both itch and inflammation. This antibacterial activity addresses the microbial driver of eczema flares without antibiotic resistance risk.

Skin barrier enhancement

Sophora flavescens extract enhances skin-barrier integrity in atopic dermatitis models: it increases cornified envelope proteins (the structural layer of the skin barrier) and hyaluronic acid (for hydration and barrier function), while reducing Staphylococcus aureus-induced inflammatory cytokines. PMID 36216196. This barrier-repairing action addresses a core deficit in eczema skin - the compromised ceramide structure that makes it permeable to irritants and allergens.

Mast cell modulation for contact dermatitis

Sophora flavescens extract modulates mast cell degranulation, directly relevant in allergic contact dermatitis and immediate-type hypersensitivity reactions in the skin. PMID 22580027

How Ku Shen works in the QICAOGANGMU formula

QICAOGANGMU combines Ku Shen at 1.5% with four other botanical actives, each addressing pathways that Ku Shen does not:

• She Chuang Zi (Cnidii Fructus) - 3%: Synergistic antipruritic via TRPV3 inhibition (a different itch pathway from Ku Shen). Antifungal against Trichophyton rubrum. Anti-allergic via mast cell stabilisation. Research confirms that the Sophora-Cnidium pairing produces greater antipruritic effect than either herb alone. PMC6151778. Cnidium monnieri chemistry and pharmacology comprehensively reviewed. PMID 32028721
• Borneolum Syntheticum (Bing Pian) - 2%: Penetration enhancer - drives Ku Shen and all other actives deeper into the stratum corneum where eczema inflammation originates, significantly increasing the bioavailability of all herbs. PMC5452010. Also provides direct TRPA1/TRPM8 antipruritic action. PMID 38103845
• Stemonae Radix (Bai Bu) - 0.5%: Broad-spectrum antimicrobial against Staph aureus, complementing Ku Shen's MRSA activity with additional bacterial strains and anti-inflammatory action via COX-2 suppression. PMID 35295975
• Menthol - 0.5%: Immediate TRPM8 cooling within minutes - providing the fast itch relief that Ku Shen's slower NF-kB modulation cannot. Clinical evidence in atopic dermatitis. PMID 30067875

Together the five herbs cover: NF-kB, STAT3, AKT1 (Ku Shen), TRPV3 (She Chuang Zi), TRPA1/TRPM8/penetration (Borneolum), Staph/COX-2 (Stemonae Radix), and TRPM8 immediate cooling (Menthol) - a breadth of coverage no single-ingredient product can match.

How to use QICAOGANGMU for eczema and psoriasis

1. Prepare the skin - wash with plain warm water only. No soap or cleanser on the inflamed area. Pat gently dry, leaving skin slightly damp for better absorption.
2. Patch test first - apply a small amount to the inner forearm for 24-48 hours before first widespread use.
3. Apply a thin layer - a pea-sized amount covers a palm-sized area. Pat gently until absorbed. Do not rub over inflamed skin.
4. Apply 2-3 times daily during active flares. Once daily for maintenance. Ku Shen's NF-kB activity builds in the skin over time - consistency determines results.
5. Continue after symptoms clear - steroid-free formula is safe for continuous long-term use without tolerance or rebound.

Frequently asked questions

What does Sophora flavescens (Ku Shen) do for eczema?

Ku Shen addresses eczema through multiple mechanisms simultaneously: NF-kB inhibition reduces the Th2 cytokine cascade that drives inflammation and itch; TSLP suppression reduces the key cytokine that triggers neurogenic itch; oxymatrine targets histamine-independent chronic itch proteins; sophoraflavanone G provides MRSA antibacterial activity protecting compromised skin; and the formula enhances the skin barrier by increasing cornified envelope proteins and hyaluronic acid. No single mechanism - multiple converging pathways working together.

Is Sophora flavescens as effective as steroid cream for eczema?

For acute severe flares, topical corticosteroids act faster. However, Ku Shen's NF-kB modulating mechanism (which preserves immune defence) vs steroid immunosuppression (which impairs it) means Ku Shen does not worsen concurrent fungal infections and has no skin-thinning, rebound, or dependency risk. Published studies show Sophora flavescens compounds reduce psoriasiform inflammation comparably to topical steroids in cellular models. PMID 38358770. For long-term chronic management, the safety profile is strongly in Ku Shen's favour.

What is the concentration of Ku Shen in QICAOGANGMU?

Sophora flavescens (Ku Shen) is present at 1.5% as Sophorae Flavescentis Radix. The full published ingredient list: Cnidii Fructus 3%, Borneolum Syntheticum 2%, Sophorae Flavescentis Radix 1.5%, Stemonae Radix 0.5%, Menthol 0.5%, Water, Glycerin, Petrolatum. For the complete evidence breakdown for every ingredient, see our full ingredients guide.

Does Ku Shen have any side effects when used topically?

Topical use of Ku Shen at standard concentrations is well-tolerated with no documented serious adverse effects in published clinical studies. The safety profile of Sophora flavescens-based preparations has been confirmed by systematic review. PMC7758483. Always patch test before first widespread use. Do not apply to broken or infected skin without medical advice. Internal use is a different matter - the alkaloids require medical supervision when taken orally; this guidance applies to topical application only.

What is the TCM pattern that Ku Shen treats?

Ku Shen is the primary herb for Damp-Heat skin conditions in TCM - the pattern characterised by redness, swelling, weeping, and itching (acute eczema and many psoriasis presentations). It is combined with Cnidii Fructus (She Chuang Zi) to enhance both the Dampness-drying and the Wind-expelling (antipruritic) actions. For a full explanation of how Damp-Heat, Wind, and Blood Heat patterns map onto modern dermatological mechanisms, see our TCM eczema deep dive.

Related articles

• QICAOGANGMU Ingredients: Full Breakdown of Every Herb, Concentration and Safety Evidence
• How TCM Explains Eczema: Wind, Dampness and Heat Deep Dive
• Is QICAOGANGMU Steroid-Free? Full Verification and Mechanism Explanation

Clinical references

1. Pan YJ et al. Anti-inflammatory activity of flavonoids and alkaloids from Sophora flavescens alleviates psoriasiform lesions. Phytotherapy Research. 2024;38(4):1951-1970. PMID 38358770
2. Yamaguchi-Miyamoto T et al. Antipruritic effects of Sophora flavescens on acute and chronic itch-related responses in mice. Biological and Pharmaceutical Bulletin. 2003;26(5):722-724. PMID 12736520
3. Jo S et al. Anti-itching and anti-inflammatory effects of kushenol F via suppression of TSLP in atopic dermatitis models. Pharmaceuticals. 2022;15(11):1347. PMID 36355519
4. Sun P et al. Sophora flavescens - Angelica sinensis pairing alleviates eczema by inhibiting TLR4/MyD88/NF-kB. Journal of Ethnopharmacology. 2024;322:117626. PMID 38154523
5. Cheng L et al. Formononetin from Sophora flavescens alleviates atopic dermatitis by suppressing NETs via PAD4/MPO inhibition. Phytotherapy Research. 2025. PMID 40635516
6. Lee JY et al. Matrine from Sophora flavescens improved DNCB eczema, reducing TNF-alpha/IL-4 and suppressing STAT3/TP53/AKT1. International Journal of Molecular Sciences. 2022;23(19):11354. PMID 36216196
7. Chunchao Han, Guo J. Sophora flavescens and Angelica sinensis: antibacterial and anti-inflammatory effects via NF-kB, IL-1beta, TNF-alpha, iNOS, COX-2. Inflammation. 2012;35(3):913-919. PMID 21976127
8. Zhou H et al. Oxymatrine from Sophora flavescens improves PASI scores in psoriasis and inhibits keratinocyte proliferation. Journal of Dermatological Treatment. 2017;28(5):463-472. PMID 28450041
9. Deng S et al. Topical herbal formulae including Sophora flavescens root improve psoriasis outcomes. British Journal of Dermatology. 2013;169(4):769-782. PMID 23817996
10. Kim H et al. Effect of Sophora flavescens extract on mast cell degranulation and contact dermatitis. Journal of Ethnopharmacology. 2012;142(1):253-258. PMID 22580027
11. Zeng J et al. Enhanced topical delivery and anti-psoriasis efficacy of Sophora flavescens in mouse models. Journal of Traditional Chinese Medical Sciences. 2025;12(1):100523. SciOpen
12. Chao X et al. Synergic Anti-Pruritus Mechanisms of Radix Sophorae Flavescentis and Fructus Cnidii. Evidence Based Complementary and Alternative Medicine. 2018. PMC6151778
13. Chen M et al. Efficacy and Safety of Sophora flavescens-based TCM. Frontiers in Pharmacology. 2020. PMC7758483
14. Matsuda H et al. Anti-allergic effects of Cnidii Monnieri Fructus. Biological and Pharmaceutical Bulletin. 2002;25(2):260-3. PMID 12081154
15. Tang B et al. Chemical constituents and pharmacological activities of Cnidium monnieri. Molecules. 2020;25(3):575. PMID 32028721
16. Li ZY et al. Borneol reduces acute and chronic itch by modulating TRPA1 and TRPM8. Frontiers in Pharmacology. 2023;14:1288289. PMID 38103845
17. Dai H et al. Clinical and mechanistic study of topical borneol-induced analgesia. Experimental and Therapeutic Medicine. 2017;13(6):3267-3272. PMC5452010
18. Xu Y et al. Alkaloids from Stemona tuberosa and their anti-inflammatory activity. Frontiers in Chemistry. 2022;10:847595. PMID 35295975
19. Misery L et al. Anti-itching effects of a TRPM8 agonist cream in atopic dermatitis. Journal of the European Academy of Dermatology and Venereology. 2019;33(2):e67-e69. PMID 30067875
20. Dong M et al. Enhanced topical delivery and anti-psoriasis efficacy of triptolide using Borneol-modified nanostructured lipid carriers. Journal of Drug Delivery Science and Technology. 2024;95:105658. PMID 39104775