What it is:
This herb is the root of Euphorbia kansui Liouex Wang (Family Euphorbiaeae), chiefly produce in Shanxi and Shaanxi provinces. The root is dug out in spring or autumn, dried in sunlight, used after process- ing with vinegar.

Property:
Bitter in flavour, cold in property, poisonous, acting on the lung, kidney and large intestine channels.

Effects:
Removing water retention, subduing swelling and resolving mass.

Used for:
1. Edema of the face and body, ascites and hydrothorax. This is a very drastic hydragogue and can bring about serious diarrhea.For treating edema and ascites, it is often used with morning glory seed, named Decoction of Two Herbs for Edema and Ascites (Erqi Tang). For vague pain in the chest and hypochondrium, and cough with dyspnea due to retention of fluid in the chest and abdomen and accumulation of phlegm, it is often used together with Chinese date, knoxia root and genkwa flower, known as Ten Jujube Decoction (Shizao Tang). For treating fluid retention compli- cated by noxious heat in the chest, it is used with rhubarb and mirabilite , named Major Decoction for Removing Phlegm-heat from Chest (Da Xianxiong Tang). In modern times, it is often used with rhubarb,magnolia bark and other herbs to treat severe intestinal obstruc- tion and intestinal hydrops, as inDecoc- tion of Kansui for Removing Intestinal Obstruction (Gansui Tongjie Tang).

2. To treat suppurative infec- tions on the body surface, the powder of kansui root is mixed with water for topical application. In addition, it has the effect of expelling phlegm, so it can be used for epilepsy due to wind-phlegm in the following way: the powder of kansui root is filled into a pig's heart and roaxted in hot ashes, and then mixed with cinnabar powder to be prepared into boluses for internal administration.

Dosage and administration: 0.5- 1g. It is better to use it in bolus or powder instead of decoction.

Precautions:
It should not be pres- cribed to pregnant women and weak patients. It is antagonistic to liquorice.