Sophora Flavescens Root
苦參 · Kǔ Shēn
Calms inflamed, weeping, relentlessly itchy skin
What it does
Where skin is weeping, raw, and relentlessly itchy rather than dry, this root is built for that exact picture. In TCM it clears heat, dries dampness, and kills parasites, covering eczema, spreading rashes, discharge, jaundice, and hot dysenteric disorder. It also promotes urination, draining what it clears out through the urine. Very bitter and very cold, it drains hard rather than gently.
Safety
- Do not exceed 9g daily. Overdose can cause spasms, slurred speech, irregular breathing, and respiratory failure.
- Mild dizziness, nausea, vomiting, or constipation can occur and usually pass on their own.
- Allergic reactions have been reported, mainly a raised blotchy rash. Stop use if a new rash appears.
- Contraindicated in cold from Spleen or Stomach deficiency. Very bitter and cold herbs are hard on weak digestion.
- Not for long unbroken courses. Classical texts warn it injures the Spleen and depletes the Kidneys.
- Not to be combined with Veratri nigri Radix et Rhizoma (lí lú); classical incompatibility.
- No safety data established for pregnancy. Consult a practitioner before use.
- AHPA Safety Class 1, Interaction Class A, with no known contraindications or drug interactions.
How to take it
Decoct 3–9g in 3 cups water for 25–30 minutes. Take it with food, since the bitterness turns the stomach on its own. For a topical wash, decoct the same amount, let it cool, and dab it on.
Use as part of Eliminate Wind Powder formula rather than as a standalone herb. The topical wash is useful for localized weeping eczema.
Where it comes from
Sophora flavescens first appears in the Divine Husbandman's Classic of the Materia Medica. Its name kǔ shēn translates literally as bitter root, and the taste lives up to it: this is one of the harshest flavors in the entire materia medica. An alternate name, niú rén shēn or ox ginseng, is where the common misreading of shēn as ginseng comes from. Classical texts filed it with the heat-clearing herbs, specifically for damp-heat that surfaces on the skin and in the lower body.