What it is:
This herb is the leaf of Isatis indigotica Fort. (family Cruciferae), produced mainly in the provinces of Jiangsu, Anhui, Fujian and Guangxi. Isatis leaves are collected in summer and autumn, dried in sunlight, and used unprepared or fresh.

Property:
Bitter in flavour very cold in pro- perty, acting on the heart, lung and stomach channels.

Effects:
Clear- ing away heat, de- toxicating, removing pathogenic heat form the blood, and curing skin erupions.

Used for:
1. Epidemic febrile diseases with the invasion of the blood by heat, mani- fested as high fever, restlessness, maculas and eruptions, un- consciousness, de- lirium and so on. It is often used with rhinoceros horn and capejasminne fruit, as in Decoction of Rhinoceros Horn and isatis leaf (Xijiao Daqing Tang). In cases of affection by exopathogenic wind- heat, of epidemic febrile diseases at the early stage, manifested as fever, headache and thirst, it is used with honeysuckle flower and arctium fruit.

2. Erysipelas, canker sores, and swollen and sore throat due to exu- berant toxic heat in the blood. It is often used with honey suckleflower and scrophularia root.

Dosage and administration: 10- 15g, decocted in water for an oral dose.