Hydrargyrum Oxydatum Crudum (Shengyao)

Naming
Sheng Yao (Hydrargyrum Oxydatum Crudum)-Yao Cai Zi Liao Hui Bian (Glossary of Reference Material of Medicinal Herbs)

Origin
Mixed sublime of mercury, nitrum and alum.

Location
Mainly in Hebei, Hubei and Hunan provinces of China, the red color one called Hong Sheng, and the yellow colour one called Huang Sheng.

The actual smell and taste
Without bad smell.

Best quality
Without shattered pieces, with luster and long time stored.

Processing
Ground into fine powders.

Property
Pungent, hot

Actions
Discharge pus and remove putridity.

Indications
The remained of pus or putrid tissue after the ulceration of abscess and deep-rooted Carbuncle make new tissue difficult to grow. This herb has a good action of discharging pus and removing putridity, so it is the key herb for discharging pus and removing putridity for surgical department. Being strong toxic, it is seldom used purely in clinic, so it is often combined with dampness-astringing and wound-healing herbs, such as calcined Gypsum Fibrosum (Shigao). The proportion of the two herbs is usually adjusted according to the disease situation. For instance, if the proportion of them is one to nine, called Jiu Yi Dan, which have weak action of draining toxin, but strong actions of astringing dampness and promoting the regeneration of tissue. If it is two to eight, called Ba Er Dan, three to seven called Qi San Dan, one to one called Wu Wu Dan and nine to one called Jiu Zhuan Dan. With the increase of the dose of Sheng Yao, the actions of draining toxin and discharging pus are gradually intensified. Meanwhile, it can be cast to the afflicted sites, or sticked to the cotron paper to insert into the pus cavity. In addition, Hydrargyri Oxydum (Shengyao) can also be indicated externally for Eczema, impetigo, stubborn tinea and Syphilis.

Dosage and administration
Take proper dose for external application.

Cautions
Being strong toxic, it can only be indicated externally. For external application, it should not be used for overdose or persistent use. The poisoning manifestations of this herb are similar to Qing Fen.