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Woad roots

Chinese: 板蓝根

Pinyin: Bǎn Lán Gēn

Parts used: Dried root

TCM category: Herbs that cool the Blood

TCM nature: Cold

TCM taste(s): Bitter

Organ affinity: Stomach Liver

Scientific name: Isatis tinctoria

Other names: Dyer's woad, Glastum

Use of woad roots (Ban Lan Gen) in TCM

Please note that you should never self-prescribe TCM ingredients. A TCM ingredient is almost never eaten on its own but as part of a formula containing several ingredients that act together. Please consult a professional TCM practitioner, they will be best able to guide you.

Preparation: Remove impurities, wash, soak in water, cut in thick slices and dry.

Dosage: 10 - 30 grams

Main actions according to TCM*: Expels Heat and Fire toxicity. Cools the Blood. Dispels Damp-Heat in the Lower Burner.

Primary conditions or symptoms for which woad roots may be prescribed by TCM doctors*: Mumps Pharyngitis Laryngitis Fever Erysipelas Carbuncles

Contraindications*: This herb should not be used by those who are without true Fire toxicity.

Common TCM formulas in which woad roots (Ban Lan Gen) are used*

Key TCM concepts behind woad roots (Ban Lan Gen)'s properties

In Traditional Chinese Medicine (TCM), woad roots are plants that belong to the 'Herbs that cool the Blood' category. Herbs in this category are used to clear inflammatory and infectious conditions, referred to as 'Internal Heat' in TCM. This is why most of the herbs in this category will have both antibacterial and antiviral properties. In TCM one has too much 'Internal Heat' in their body as a result of a deficiency of 'Yin' (which is Cold in nature, see our explanation on Yin and Yang) or, more commonly, an Excess of Yang (Hot in nature). Herbs that cool the Blood treat the latter and as such tend to be Cold or Neutral in nature.

As suggested by its category woad roots are plants that are Cold in nature. This means that woad roots typically help people who have too much 'Heat' in their body. Balance between Yin and Yang is a key health concept in TCM. Those who have too much Heat in their body are said to either have a Yang Excess (because Yang is Hot in nature) or a Yin deficiency (Yin is Cold in Nature). Depending on your condition woad roots can help restore a harmonious balance between Yin and Yang.

Woad roots also taste Bitter. The so-called 'Five Phases' theory in Chinese Medicine states that the taste of TCM ingredients is a key determinant of their action in the body. Bitter ingredients like woad roots tend to have a cleansing action on the body by clearing Heat, drying Dampness and promoting elimination via urination or bowel movements.

The tastes of ingredients in TCM also determine what Organs and Meridians they target. As such woad roots are thought to target the Stomach and the Liver. In TCM the Stomach is responsible for receiving and ripening ingested food and fluids. It is also tasked with descending the digested elements downwards to the Small Intestine. The Liver on the other hand is often referred as the body's "general" because it is in charge of regulating the movements of Qi and the Body Fluids. It also takes a leading role in balancing our emotions.

Research on woad roots (Ban Lan Gen)

Woad root eyedrops have an excellent efficacy and safety on the acute bacterial conjunctivitis.1

Huanglan Granule (containing woad root) has obvious inhibitory effect on the rubella virus.2


1. Qi CX, Wu XM, Wang XL. (2007 ). Clinical research of isatis root eyedrops on the acute bacterial conjunctivitis. Zhong Yao Cai. , 30(1):120-2.

2. He Y, Hao XP, Yang D. (2008). Clinical and experimental study on effects of huanglan granule in inhibiting rubella virus. Zhongguo Zhong Xi Yi Jie He Za Zhi. , 28(4):322-5.