Gypsum is a commonly used traditional Chinese medicine for clearing heat and eliminating fire. However, it should not be taken by those with weak spleen and stomach, blood deficiency, or yin deficiency with fever. So how is it determined whether gypsum should be decocted first or decocted for a long time?
Gypsum has the effect of treating phlegm heat and wheezing. It can be ground into powder with equal amounts of gypsum and cold water stone, and then mixed with three qian (about 9 grams) of the powder in a decoction of ginseng. It should be taken after meals.
Many doctors require gypsum to be decocted first or decocted for a long time in order to fully extract its effective ingredients, but some people think it is unnecessary. Research has shown that decocting gypsum first is not in accordance with the traditional method.
Studies have shown that the main component of gypsum is calcium sulfate hydrate, and its solubility decreases with increasing temperature. The content of the main component of gypsum decreases after it is decocted first or decocted for a long time. Chinese herbal medicine has complex components, and the antipyretic effect of gypsum is the result of the participation of calcium sulfate and other trace elements.
In the "Treatise on Cold Damage" and "Synopsis of Prescriptions of the Golden Chamber", all prescriptions containing gypsum, such as Bai Hu Tang, Bai Hu Jia Ren Shen Tang, Da Qing Long Tang, Zhu Ye Shi Gao Tang, Ma Huang Sheng Ma Tang, Fu Zi Jing Mi Tang, Yue Bi Tang, and Hou Po Ma Huang Tang, are decocted together with other drugs without indicating whether gypsum should be decocted first or decocted for a long time.
Therefore, when using gypsum in prescriptions, we must strictly follow Zhang Zhongjing's principles of medication, and gypsum should not be decocted first or decocted for a long time.
It should be avoided by those with weak spleen and stomach and yin deficiency with fever. Gypsum has a strong cold nature, which can easily damage the spleen and stomach yang. It should be used with caution by those with weak spleen and stomach. For raw gypsum, 15-60 grams should be crushed and decocted first; for calcined gypsum used externally, an appropriate amount should be ground into powder and applied to the affected area.
