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Sophorae Flavescentis Radix (Ku Shen)

Sophorae Flavescentis Radix (Ku Shen)

What is Sophorae Flavescentis Radix (Ku Shen)?

Sophorae Flavescentis Radix (ku shen, 苦参), also known as Lightyellow Sophora Root, refers to the roots of Sophora flavescens Ait, a hardy deciduous shrub in the family Leguminosae. Native to China, Japan, Korea and Russia, the plant can reach a height of approximately five feet, and its roots range between four and 12 inches in length . Usually brown and curved, these roots have small cracks or ridges on its outer surface.

Though its name in Chinese means ‘bitter ginseng’, Ku Shen is not related to Ginseng at all. First mentioned in Shen Nong’s Herbal Classic (神农本草经), Sophorae Flavescentis Radix is viewed as one of the medium-grade herbs that may be poisonous but can heal sickness and tonify Deficiencies when used appropriately.

After bundling the roots, Sophorae Flavescentis Radix are cleansed, sliced and dried under the sun for medicinal usage. While the herb can be used raw, it is also consumed in various forms such as extracts, powder, capsules, tea and other supplements.

In Traditional Chinese Medicine (TCM), Sophorae Flavescentis Radix falls under the category of ‘Herbs that clear Heat and dry Dampness’. Such herbs can clear inflammatory and infectious conditions, referred to as Internal Heat in TCM. Cold in nature, Sophorae Flavescentis Radix can help individuals with too much Heat in their body, such as those experiencing a yang excess or a yin deficiency, to restore a harmonious yin-yang balance.

Bitter in taste, Sophorae Flavescentis Radix can cleanse the body by clearing Heat, drying Dampness and promoting elimination via urination or bowel movements. In particular, the herb targets the bladder, the Heart, the large intestine, the Liver and the stomach.

Functions and Benefits of Sophorae Flavescentis Radix (Ku Shen)

Traditional Chinese Medicine (TCM) shows that Sophorae Flavescentis Radix has the following health benefits.

Sophorae Flavescentis Radix can clear Heat and dry Dampness to treat Damp-Heat syndromes, and induce diuresis to drive pathogenic Damp-Heat out of the body. For example, Sophorae Flavescentis Radix can address jaundice, leukorrhagia, eczema, sores, difficulty in urinating, damp and swollen scrotum, and bleeding hemorrhoids. To treat dysentery with pus and blood discharge or painful diarrhea, you can combine Sophorae Flavescentis Radix with other Heat-clearing and Dampness-driving herbs to enhance its effectiveness. 

Sophorae Flavescentis Radix can purge fire and remove toxicity to address Heat-toxin syndromes such as sores, abscesses, sore throat, swollen and painful gums. In addition, Sophorae Flavescentis Radix can be used topically and externally to kill parasites and relieve skin discomfort such as scabies, skin itching, trichomonas vaginal itching and leukorrhagia.

For acute urinary tract infections caused by Heat, edema caused by Heat and accumulation of Damp-Heat in the small intestine, Sophorae Flavescentis Radix can also promote urination to address these issues.

Sophorae Flavescentis Radix (Ku Shen) close up
Sophorae Flavescentis Radix (Ku Shen) can help to ease difficult urination.

How to Use Sophorae Flavescentis Radix (Ku Shen)

For internal usage, the recommended daily dosage of Sophorae Flavescentis Radix is 3 – 10g. However, some healthcare practitioners may recommend a higher dose of 30 – 60g to treat arrhythmia. Sophorae Flavescentis Radix is also often combined with other herbs as part of a larger herbal formula to treat specific conditions.

Dried, sliced Sophorae Flavescentis Radix can be found at many herbal shops and Asian markets. Sophorae Flavescentis Radix is also available in supplement forms such as powder, pill and decoction.

Cautions and Side Effects of Sophorae Flavescentis Radix (Ku Shen)

Sophorae Flavescentis Radix should not be used by individuals who are experiencing excess Cold in the Spleen and stomach. Patients on heart or blood pressure medications should also avoid this herb as it has effects on the heart and central nervous system.

Overconsumption of Sophorae Flavescentis Radix may weaken one’s appetite. Also, Sophorae Flavescentis Radix contains matrine. Large amounts of matrine may cause toxicity in some individuals. 

Sophorae Flavescentis Radix should not be used together with Veratrum Root and Rhizome (Li Lu, 藜芦), Cuscuta Seeds (Tu Si Zi, 菟丝子) and Unibract Fritillary Bulb (Bei Mu, 贝母).

We strongly encourage you to consult your healthcare provider before deciding to add Sophorae Flavescentis Radix to your healthcare routine.


Here is a summary for Sophorae Flavescentis Radix (Ku Shen):

  • Herb name (Chinese): 苦参
  • Herb name (Pin Yin): kǔ shēn
  • Herb name (English): Lightyellow Sophora Root
  • Herb name (Botanical): Radix Sophorae Flavescentis
  • Origin of species: Sophora flavescens Ait.
  • Part(s) of herb used: Root
  • Geo-specific habitat(s): Many parts of China
  • Taste(s) & Properties: Bitter; Cold; Administrates the Heart, Liver, Stomach, Large Intestine and Bladder Meridians
  • Actions: Eases skin irritations, such as those around the pubic region; Eases difficult urination; Relieves symptoms of dysentery and jaundice

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