Pingwei San (Stomach-Calming Powder): Drying Dampness and Strengthening the Spleen, Moving Qi and Harmonizing the Stomach
Pingwei San is an ancient formula composed of four herbs—Cangzhu (Atractylodes lancea), Houpo (Magnolia bark), Chenpi (tangerine peel), and Chao Gancao (stir-fried Glycyrrhiza)—in a ratio of 4:3:2:1. The herbs are ground together into a fine powder to make a powder preparation; each time, take 1–2 qian (5–10 g) of the powder, decocted with two slices of Shengjiang (fresh ginger) and two Dazao (jujubes) as a guide, and taken orally. Today there are Chinese patent medicines based on the formula, Pingwei Wan or Xiangsha Pingwei Wan, sold in most pharmacies. Xiangsha Pingwei Wan is formed by augmenting Pingwei San with Muxiang (Aucklandia) and Sharen (Amomum villosum), and its action of countering upward rebellion and strengthening the stomach is even more pronounced.
According to traditional TCM theory, Pingwei San has the actions of drying dampness and strengthening the spleen, moving qi and harmonizing the stomach, and can be used for the syndrome of dampness stagnating in the spleen and stomach. If the patient presents with epigastric and abdominal distending pain, no desire to eat, bland taste in the mouth, nausea and vomiting, belching and acid regurgitation, heavy limbs, lassitude and a desire to sleep, frequent loose stools, a white greasy and thick tongue coating, and a moderate or slow pulse, Pingwei San may be used for treatment.
Pingwei San is also a formula very suitable for cancer patients who develop nausea, vomiting and inability to eat during chemotherapy. If the patient is receiving chemotherapy in a hospital and it is inconvenient to decoct herbs, they may simply buy Pingwei Wan or Xiangsha Pingwei Wan. Pingwei San is also commonly used in treating digestive diseases such as acute and chronic gastritis, gastric and duodenal ulcers, intestinal obstruction, irritable bowel syndrome, and infectious hepatitis. Patients with the above diseases who present with the symptoms of dampness stagnating in the spleen and stomach may all try Pingwei San or Pingwei Wan for relief.
But for clinicians, knowing only Pingwei San is not enough; they must also learn to use its derivative formulas.
Pingwei San plus Gehua (Pueraria flower) is called Gehua Pingwei San; Gehua Pingwei San is a famous ancient formula for sobering up. Intoxicated patients often present with the above symptoms; Pingwei San can relieve the symptoms of drunkenness, and Gehua is a fine herb for dispelling alcohol, so the combination is a good formula for sobering up.
Zhilian Pingwei San is formed by adding Zhizi (Gardenia), Huanglian (Coptis), Gegen (Pueraria root) and Zhuru (bamboo shavings) to Pingwei San; Zhilian Pingwei San can treat the syndrome of damp-heat in the spleen and stomach, in which patients commonly present with hiccups, heartburn, loose or watery stools. The Zhilian Pingwei San in Zheng Yin Mai Zhi (Treatment of Causes, Symptoms and Pulses) is composed of Shanzhizi (Gardenia), Chuan Huanglian, cooked Cangzhu, Houpo, Guangchenpi, Gancao, Gegen, Mugua (Chaenomeles fruit) and Qinjiao (Gentiana macrophylla); this formula treats deviation of the mouth and eyes caused by facial palsy, drooling at the corner of the mouth, slurred speech, and a wiry and rapid right-guan pulse, because the ancients believed this disease was caused by stomach heat.
Shanghan Dabai contains a Pingwei Fabiao Tang (Stomach-Calming Exterior-Releasing Decoction), composed of Qianghuo (Notopterygium), Chaihu (Bupleurum), Gange (Pueraria root), Zhishi (immature bitter orange), Houpo, Banxia (Pinellia) and Guangchenpi; this is a variant of Pingwei San. Zheng Yin Mai Zhi also has a Pingwei Fabiao Tang, which is formed by adding Zhiqiao (bitter orange), Houpo, Banxia and Jupi (tangerine peel) to Baidu San. Both formulas are good for treating colds that present with both an exterior syndrome and stomach stagnation; what we today call gastrointestinal cold belongs to this category.
Combining Pingwei San with Baohe Wan gives Pingwei Baohe Tang. The Pingwei Baohe Tang recorded in volume nine of Songya Zunsheng is composed of one qian each of Cangzhu, Houpo, Zhishi, Chenpi, Laifu (radish seed), Shanzha (hawthorn) and Xiangfu (Cyperus), plus five fen of Zhi Gancao (honey-fried Glycyrrhiza); it mainly treats food accumulation and heart pain as if something were lodged and unable to descend. The Pingwei Baohe Tang in Zheng Yin Mai Zhi is composed of Cangzhu, Houpo, Chenpi, Gancao, Laifuzi, Shanzha, Maiya (barley sprout), Shenqu (medicinal leaven) and Lianqiao (Forsythia), and mainly treats abdominal pain and headache due to food accumulation. Zheng Yin Mai Zhi especially emphasizes that Pingwei Baohe San (Tang) is very effective for headache, whether the headache is due to external contraction or internal injury.
San Yin Ji Yi Bing Zheng Fang Lun contains a "Bawei Pingwei San" (Eight-Ingredient Stomach-Calming Powder), composed of one and a half liang each of Houpo, Shengma (Cimicifuga), Shegan (Belamcanda) and Fuling (Poria), one liang each of Dahuang (rhubarb, steamed), Zhiqiao (pith removed, bran-fried) and Gancao (honey-fried), and half a liang of Shaoyao (Paeonia). This formula mainly treats injury to the stomach by food, with vomiting of several mouthfuls of clear acid water every morning, or a constant sour sensation in the chest, and nothing else during the day.
Zheng Yin Mai Zhi also contains Shenzhu Pingwei San, composed of Cangzhu, Fangfeng (Saposhnikovia), Gancao, Shigao (gypsum), Zhimu (Anemarrhena), Houpo and Chenpi; this formula mainly treats the heat syndrome in which there is both external contraction and stomach-stagnation stomach pain.
In addition, Pingwei San plus Shijunzi (Quisqualis fruit) can treat stomach pain due to worm accumulation. Combining Pingwei San with Daotan Tang gives Pingwei Daotan Tang, which can treat stomach pain caused by phlegm-fluid. Combining Pingwei San with Erchen Tang gives Erchen Pingwei San, which can also treat stomach pain caused by phlegm-fluid.