The Single-Herbal Formula Mishi Shiwei San for Ascites
"Mishi Shiwei San" (Secret Pyrrosia Powder) comes from Feng Lao Gu Ge. The formula is simple, containing only two herbs: Folium Pyrrosiae (Shiwei, stir-fried with vinegar) 2 qian (6 g), Radix Aucklandiae (Muxiang) 3 qian (9 g). Grind the above medicines together into a powder; each time take 1 qian 2 fen (3.6 g), stirred into clear boiled water. This formula moves qi and promotes urination; it is mainly used for edema and tympanites (abdominal distension) resulting from qi stagnation and damp obstruction — this disease is ascites in modern medicine.
The Pyrrosia in this formula is the dried leaf of Pyrrosia sheareri (Bak.) Ching of the Polypodiaceae family. It mainly promotes urination and unblocks strangury, clears lung heat and stops cough, and cools blood to stop bleeding. It is used for heat strangury, blood strangury, stone strangury, edema, lung-heat cough and wheezing, heat-in-blood metrorrhagia, hematemesis and epistaxis. Modern pharmacological research shows Pyrrosia has antiviral, antibacterial, antitussive, expectorant and leukocyte-raising effects. Pyrrosia is a commonly used TCM herb for ascites-type diseases and also for stones; when treating stones it is often combined with Spora Lygodii (Haijinsha).
The Aucklandia in this formula is the dried root of Aucklandia lappa Decne. of the Compositae family, with a special fragrance. It belongs to the qi-regulating herbs in TCM. Traditional TCM holds that it moves qi and stops pain, harmonizes the middle and removes distension. It is mainly used for spleen-stomach qi stagnation, epigastric and abdominal distending pain, dysentery, diarrhea from food retention, and abdominal distension from spleen deficiency with qi stagnation. In modern times it is often used to treat digestive tract diseases such as gastritis and hepatobiliary diseases. Modern pharmacological research shows Aucklandia can counteract intestinal spasm, dilate blood vessels, lower blood pressure, and exert antibacterial effects.
Aucklandia also has a good diuretic effect. Professor Qian Ying, a Beijing expert on hepatobiliary diseases, frequently used Aucklandia combined with Magnolia Bark to treat ascites during his lifetime. He found that when Aucklandia and Magnolia Bark were added to a formula, the patient's urine output increased markedly and ascites resolved more quickly; without them, the diuretic and detumescence effect was much weaker.
This formula pairs Pyrrosia with Aucklandia, making the diuretic and detumescence effect even more pronounced. It can be used as a small single formula, or as a medicinal pair added to formulas treating hepatic ascites to enhance their effect.