Shugan Yin: Liver-Soothing Drink to Move Qi and Stop Pain
Shugan Yin comes from Lu Fu Jin Fang (Forbidden Formulas of the Lu Princely Household). It consists of Huanglian (coptis) 2 qian (6 g, stir-fried with evodia juice), Danggui (angelica) and Chaihu (bupleurum) each 1.5 qian (4.5 g), Qingpi (green tangerine peel) 1 qian (3 g), Taoren (peach kernel, ground to a paste) 1 qian (3 g), Chuanxiong (Sichuan lovage) and Baishao (white peony, wine-fried) each 1 qian 1 fen (3.3 g), and Honghua (safflower) 5 fen (1.5 g). Decoct in water, strain, and take warm after meals, twice daily. Shugan Yin soothes the liver and moves qi, activates blood and unblocks the collaterals. It treats qi stagnation and blood stasis in the liver channel with pain below the left hypochondrium.
Coptis stir-fried with evodia juice is in fact Zuojin Wan (Left Metal Pill), which comes from Danxi Xin Fa and is Zhu Danxi's empirical formula. Zuojin Wan treats liver fire invading the stomach with gastric discomfort and acid regurgitation, vomiting and hypochondriac pain, tendon hernia with glomus binding, and cholera with muscle cramps. In it, coptis has broad-spectrum antibacterial and anti-inflammatory action and is a common medicinal for acute gastroenteritis, cholecystitis, and other digestive inflammations; evodia stops vomiting. Thus Zuojin Wan, made of these two, relieves the vomiting and diarrhea, acid regurgitation, and hypochondriac pain caused by such diseases.
On the basis of Zuojin Wan, Shugan Yin adds liver-soothing and blood-activating medicinals such as bupleurum, angelica, green tangerine peel, peach kernel, white peony, Sichuan lovage, and safflower. This formula can also be seen as a modification combining Zuojin Wan with Chaihu Shugan San. Chaihu Shugan San is made of Chenpi (tangerine peel), Chaihu, Chuanxiong, Xiangfu (cyperus), Zhiqiao (bitter orange), Shaoyao (peony), and Gancao (licorice), its main action being to move qi and stop pain. Shugan Yin replaces tangerine peel with green tangerine peel, which moves qi and stops pain more strongly, drops the cyperus, bitter orange, and licorice of Chaihu Shugan San, and adds the blood-activating, stasis-resolving peach kernel and safflower; hence its emphasis is on resolving stasis to stop pain.
Shugan Yin treats the liver-channel qi stagnation and blood stasis caused by conditions somewhat harder to treat than ordinary acute gastroenteritis—chronic hepatitis, cholecystitis, pancreatitis, gastroenteritis, fatty liver, cirrhosis, and tumors of the hepatobiliary and pancreatic systems. The main clinical signs are distending or stabbing pain below the left hypochondrium, worsening after meals, and worst of all in the afternoon. In the author's experience, combining Shugan Yin with Jinlingzi San (made of Yanhusuo/corydalis and Chuanlianzi/toosendan fruit) gives a better pain-relieving effect.
The rationale of a large formula is usually hard to grasp; breaking it into smaller formulas makes it easier to understand the medication logic of the physicians who created it. Only by mastering the rationale of TCM formulas can we better match medication to the pattern in clinical practice.