• Excerpted from Bensky:  Chinese Herbal Medicine Materia Medica, 3rd ed.

Generally applied externally as a fine powder. Its dispersing property has been removed, and it is somewhat less cold, but its abilities to restrain and generate flesh are enhanced. It is frequently used externally for eczema, scalding and erupted sores or wounds that fail to heal. However, it is also included in a number of classical formulas for internal use. Harm and benefit in the Materia Medica notes that calcined gypsum is not as harmful to the Stomach as the unprepared form, especially if missed with rock sugar, but it will be ineffective if used in small doses. However, Zhang Xi-Chun and others object that once calcined, its ability to vent and release the muscle layer is lost, and if used internally for externally contracted pathogens coupled with heat from excess, it will instead restrain phlegm-fire and lead to clumping and other toxic effects. This, at present, calcined gypsum is usually only applied externally.

• According to the philippe sionneau pao zhi book, duan (calcined ) shi gao is for vacuity LU/St heat

Shi Gao Duan (cooked/calcined) - Gypsum fibrosum