Pharmaceutical Latin: Crudum Hydragyrum Oxydatum
Common English: Mercuric Oxide
Herbs for External Application
Taste Temperature Entering Meridians Dosage
Very Toxic
Actions Indications/Syndromes

Discharges pus and removes putridity topically

Eczema, impetigo, stubborn tinea and syphilis

  • For external application only.
  • Do overdose or use long-term.







  1. The remainder of pus or putrid tissue after ulceration of abscesses and deep-rooted carbuncles makes new tissue difficult to grow. This herb has a good effect in discharging pus and removing putridity, so it is the key herb for discharging pus and removing putridity for surgery. Being strongly toxic, it is seldom used purely in the clinic. It is often combined with Dampness-astringing and wound-healing herbs, such as calcined Gypsum Fibrosum Duan Shi Gao. The proportion of the two herbs is usually adjusted according to the disease situation. For instance, if the proportion is one to nine, it is called Jiu Yi Dan, which has a weak action of draining toxins, but a strong action in astringing Dampness and promoting the regeneration of tissue. If it is two to eight, it 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 dosage of Sheng Yao, the actions of draining toxins and discharging pus are gradually intensified. It can be applied to the affected sites, or stuck to cotton and inserted into the pus cavity. Sheng Yao can also be used externally for eczema, impetigo, stubborn tinea and syphilis.