Understanding Zuo Jin Wan
Understanding Zuo Jin Wan
By Eric Brand
Zuo Jin Wan is a very small but special formula. It clears and drains liver fire, downbears counterflow and checks vomiting. As a small formula unit, it can be easily added to other prescriptions, such as Chai Hu Shu Gan San (Bupleurum Liver-Coursing Powder) or prescriptions created to harmonize the stomach and treat vomiting of acidic liquid.
Zuo Jin Wan treats liver fire invading the stomach. There may be pain in the rib-sides, “clamoring stomach” (like pain but not pain, like hunger but not hunger), acid swallowing (upflow of acid that is immediately swallowed), vomiting, bitter taste in the mouth, a red tongue with yellow fur, and a wiry rapid pulse.
This formula is used when liver depression forms fire and counterflows transversely to invade the stomach, causing liver-stomach disharmony. Inhibited qi in the liver channel causes distention and pain of the rib-sides, while liver fire invading the stomach produces the loss of the stomach’s harmonious downbearing, resulting in clamoring stomach, acid swallowing, vomiting, and belching. Internal exuberance of liver fire causes the tongue and pulse presentation.
In the section on the 19 pathomechanisms, the Nèi Jīng states that “all counterflow upsurging is ascribed to fire,” and also states that “all sour retching and vomiting…is ascribed to heat.” This is the underlying theory within this formula, but the special relationship of Huang Lian (Coptidis Rhizoma) and Wu Zhu Yu (Evodiae Fructus) is its most unique feature.
Huang Lian enters the heart, liver, and stomach channels, and it directly clears liver fire. When liver fire is cleared, it no longer invades the stomach. It also drains stomach fire; when stomach fire is cleared, the stomach qi downbears on its own. Additionally, Huang Lian drains heart fire, which corresponds to the principle of “treating repletion by draining the child.”
If only bitter-cold medicinals are used to treat fire depressed in the liver channel, there is a fear that the coolness will cause obstruction and make the condition difficult to resolve. Therefore, a small amount of Wu Zhu Yu is used to open liver depression and downbear stomach counterflow. Wu Zhu Yu helps Huang Lian to harmonize the stomach and check vomiting while also preventing damage to the stomach from the large quantity of bitter-cold Huang Lian. Wu Zhu Yu also helps guide Huang Lian to the liver channel, so some texts consider it to be a courier in addition to being a paradoxical assistant.
The combination of one cold and one hot medicinal in Zuo Jin Wan is very notable, and the formula has been studied extensively for many different clinical indications. Additionally, research has been done to evaluate the effects of decocting these two medicinals together, and it appears that the dosage of the two medicinals in relationship to each other affects the yield of suspected active chemical constituents. Different dose relationships of Huang Lian to Wu Zhu Yu have been recorded in Chinese medical history, but the most prominent ratio is 6 parts of Huang Lian to 1 part of Wu Zhu Yu (from Zhu Dan-Xi). Wu Zhu Yu can also be stir-fried with Huang Lian to moderate its cold nature and draw from the principles of the formula Zuo Jin Wan.