The astringent herbs have the function of stabilizing the Essence, Body Fluids and Qi. They treat abnormal discharge of the essential substances of the body through excessive sweating, vomiting, urination, spermatorrhea and diarrhea. They can also treat abnormal consumption of the Qi from excessive coughing, shortness of breath, asthma and palpitations. They are sometimes used to stabilize the structure of organs and keep them from slipping from their proper positions in the condition of Qi deficiency, such as seen in prolapse of the rectum or uterus.

The cause of abnormal discharge of the essential substances is Qi deficiency. When the internal organs are very weak, the Qi is not strong enough to keep the Essence and Body Fluids in the body and to keep the organ in its proper place and position, so this disorder occurs. Elderly people and those with chronic disease or a very weak constitution are more likely to have this disorder. The herbs that stabilize abnormal discharge of the essential substances focus on treating the manifestations; however, they have little influence on the organ itself and do not treat the cause, so they should be used together with herbs that treat the causes.

Most of the herbs that stabilize the Qi, Essence and Body Fluids are sour or astringent. Sourness has a contracting ability and an inwards-moving tendency. Herbs with an astringent property are able to prevent or reverse the abnormal leakage of the Qi, Essence and Body Fluids. Of these herbs, some particularly stabilize the Lung-Qi; others are effective at stabilizing the Heart-Qi or the Kidney-Essence, or binding up the intestines.

In clinical practice, the astringent herbs should be used with caution. First of all, as mentioned above, since these herbs treat only the manifestations, they should be combined with herbs that treat the causes of the disorders. To treat chronic conditions, astringent herbs should be used with herbs that tonify the Qi in order to treat the abnormal discharge completely. In acute conditions—such as in excessive sweating and diarrhea—the astringent herbs can be used alone; however, when the condition is stabilized the appropriate tonifying herbs should then be used immediately.

Secondly, astringent herbs should be used only in Deficiency syndromes. They are prohibited for use in Excess syndromes or syndromes in which Deficiency and Excess coexist—for instance, where there is Dampness, Phlegm and Heat. This is because these herbs are able to stabilize the Essence and Body Fluids, so they can also retain pathogenic factors within the body.

There are many factors that can cause abnormal discharge of the Body Fluids and Essence, therefore correct differentiation of the syndrome is required. The astringent herbs are prohibited for use in the following syndromes: diarrhea caused by Damp-Heat in the intestines, excessive urination or spermatorrhea caused by Damp-Heat in the Lower Jiao, shortness of breath due to accumulation of Phlegm, or excessive sweating due to Excessive- or Deficient-Heat in the body.

The commonly used herbs that particularly stabilize the Lung-Qi are Wu Wei Zi ( Schisandrae fructus), Wu Mei ( Mume fructus), He Zi ( Chebulae fructus) and Bai Guo ( Ginkgo semen). The herbs that stabilize the Lung-Qi can be used to relieve thirst and shortness of breath, and are used in the treatment of asthma, pulmonary pneumonia, pulmonary emphysema, acute and chronic bronchitis, cough and hyperventilation.