What it is:
Gypsum is of the hard gypsum family of sulphate minerals and contains mainly hydrated calcium sulphate. The provinces of Hubei, Anhui, Henan and Shandong are the main sources of gypsum. It is mind all the year round, ground after getting rid of impurities, and used unprepared or calcined.

Property:
Pungent and sweet in flavour, cold in property, acting on the lung and stomach channels.

Effects:
Clearing away heat and pur- ging fire, relieving thirst and rest- lessness, and promoting regeneration of the tissue and wound healing.

Used for:
1. Acute febrile diseases with pathogenic factors in the qi system, shown as high fever, dysphoria, thirst, sweating, full pulse and other heat symptoms of excess type. It is often used with anemarrhena, polished rice and liquorice, known as White Tiger Decoction (Baihu Tang). For skin erup- tion and ecchymoses and retained high fever due to obstruction of excessive noxious heat it can be used with rhinoceros horn and scrophularia root, as in Decoction for Relieving Feverish Rash (Huaban Tang). For febrile diseases in the later stage with lingering fever, dysphoria, thirst and red tongue with very little fur, it is used with lopha- therum and ophiopogon root, as in Decoction of Lophatherum and Gypsum (Zhuye Shigao Tang).

2. Asthma, shortness of breath, vexation and thirst due to excessive lung-heat.It is often used with ephedra, bitter apricot kernel and liquorice, named Decoction of Ephedra, Apricot Kernel, Gypsum and Liquorice(Ma Xing Shi Gan Tang).

3. Headache and swollen and painful gum due to rising up of stomach- fire. It is often used with rehmannia root, achyranthes root, anemarrhena and so on, as in Gypsum Deception (Yunu Jian).

4. Slow- healing ulcerated sores, eczema, burns and scald. gypsum is calcined and ground into fine powder for external use. For non- healing of sores with difficulty in regeneration of tissue, it is often used with herbs having actions of lifting the vital engrgy, as in Nine to One Pellet(Jiu Yi Dan).

Dosage and administration: 15- 60g, decocted in water prior to other herbs for an oral dose. Proper dosage for external use. For clearing away heat and purging fire, it should be used unprepared; for promoting regeneration of tissue and healing of wounds, it should be calcined.

Precautions:
Gypsum is contraindicated for cold syndrome of deficiency type in the spleen and stomach and interior heat-syndrome due to yin deficiency.