The source is from the compound prepared from equal amount of mercury, nitre and alum through sublimation. The medicine may be red or yellow in color, the red one is called Hongsheng; the yellow one Huangsheng. It is mainly produced in Hebei, Hunan, and Jiangsu provinces. It is ground into powder for medicinal use and more effective if stored over a long time.

Medicinal Properties: Pungent in flavor and hot in nature, toxic and attributive to the lung and spleen meridians.

Actions: Remove toxin and necrotic tissue to regenerate tissues.

Application
In treating ulceration from carbuncle or phlegmon failing to evacuate pus smoothly and necrotic tissue, it is often used in combination with Duanshigao (Gypsum Fibrosum Usta), which is ground into powder for external use. The ratio of Duanshigao (Gypsum Fibrosum Usta) and Hongsheng is 9 : 1, which is called Jiuyi Dan (Pill) with weak action of removing toxin. When the ratio of the two is 1 ：1, the composition is called Wuwu Dan (Pill) with strong action of removing toxin. When the ratio is 1 ：9, the composition is called Jiuzhuan Dan (Pill), its action of removing toxin being strongest. These can be selected according to disease conditions. They can be applied to the local area, or stuck to a paper spill and inserted into the vomica.

Usage and Dosage: Proper amount is for external use. It is usually used in combination with other Chinese herbs and is not used singly.

Notes: It has strong toxicity, is only for external use but not for oral use. It is not suitable for pyocutaneous dosease without necrotic tissues or pus.