What it is:
Mirabilite whose main content is hydrated sodium sulphate, is the Crystal of the refined mirabilite from the sulphate minerals. It is mainly produced in Hebei, henan and Shandong provinces. The natural sulphate minerals are dissolved in hot water and them boiled together with carrot slices. Decant the supernatant and cool it until it is crystallized. Through weathering, mirabilite loses the crystalline water and presents a white powder called dried glauber's salt.

Property:
Salty and bitter in flavour, cold in property, acting on the stomach and large intestine channels.

Effects:
Softening hard masses by purgation and clearing away heat and toxins.

Used for:
1. Constipation due to accumulation and retention of heat of excess type in the stomach and intestines. It is used with rhubarb , as in Major Decoction for Purging Down Digestive Qi (Da Chengqi Tang) and Purgative Decoction for Coordinating the Function of the Stomach (Tiaowei Chengqi Tang).

2. Sore throat, canker sores and blood-shot eyes. mirabilite for external use is capable of clearing away heat and virulence of pathogenic organisms, and is often used in combination with borax and borneol for sore throat and canker sores, as in borneol and Borax Powder (Bing Peng San). For treating blood-shot eyes, dried glaruber's salt is spread on some bean curd and dissolved by steaming it together with the bean cured to obtain a liquid which is used as eye drops. In addition, it can be used for external application to treat abscess and swelling breasts, and can be used as lactifuge.

Dosage and administration: 10- 15g, infused in the decoction of the herbs or dissolved in boiling water for oral administration. Proper dosage for external use.

Precautions:
It is contraindicated for pregnant women.