Ban Lan Gen: Chinese Herb Guide

Name

Ban Lan Gen (Radix Isatidis), recorded in Xinxiu Bencao.

Source and quality

Plant

The root of the biennial Isatis indigotica Fort., family Cruciferae.

Where it is grown

Shaanxi, Hebei, Jiangsu, Zhejiang and Anhui provinces.

Harvest

Collected in autumn.

Smell and taste

Faint smell; slightly sweet, bitter and astringent.

Better grade

Straight, thick and even root, solid and sufficiently mealy.

Processing

Sliced; used raw.

Nature and action

Bitter and cold; enters the lung, stomach, heart and liver channels. Clears heat and removes toxicity, cools the blood, and relieves sore throat.

When it is used

Warm disease and external invasion of wind-heat

Ban Lan Gen and Da Qing Ye come from the same plant, Isatis indigotica, but use different medicinal parts. They are similar in nature and action: both clear heat and purge fire when the heat enters the qi system, and both clear heat and cool the blood when it enters the blood system. Both are widely indicated at every stage of warm disease and in exterior wind-heat patterns, and they are commonly combined for mumps, erysipelas and fever with a swollen head from warm-toxin, each reinforcing the other.

Although its action of cooling the blood and clearing macular rash is not as strong as Da Qing Ye's, it specializes in removing toxicity, relieving sore throat and reducing swelling, which makes it the right choice for early warm disease or exterior wind-heat marked by fever and sore throat. It is used in Gan Mao Tui Re Chong Ji from the Pharmacopoeia of the People's Republic of China published in 1990, and is also often combined with herbs good at dispersing wind-heat to strengthen the effect, such as Bo He, Jin Yin Hua and Lian Qiao.

Where the heat blazes in both the qi and blood systems, or enters the nutrient and blood with high fever and macular rash, it is used to clear heat and remove toxicity and to cool the blood and clear the rash, and is often combined with other toxicity-removing and blood-cooling herbs so that heat is cleared from both systems: with Huang Qin, Zi Cao and Sheng Di Huang in Shen Xi Dan from Wenbing Tiaobian.

Swollen and sore throat

It is good at clearing heat from the heart and removing toxicity, and clearing heat from the lung and stomach to relieve sore throat and dissipate nodules. It is commonly used for a red, swollen, sore throat and red, swollen, painful cheeks, where the cause is interior excess heat-toxin, invasion by epidemic toxicity, or wind-heat.

It may be used alone, or combined with herbs that disperse wind-heat, remove toxicity and relieve the throat, such as Niu Bang Zi, Xuan Shen and Jie Geng in Pu Ji Xiao Du Yin from Dong Yuan Shi Xiao Fang.

Separately, because it clears heat, removes toxicity and cools the blood, it is also suited to sores and swollen, painful abscesses, red eyes, and vomiting of blood or nosebleed from blood heat.

Dose

Decoction 15~30 g, or 60~120 g as a large dose; also made into pills or powder. Use externally as appropriate.