Da Bu Yin Tang (Major Yin-Supplementing Decoction) for Edema in the Luoshi Huiyue Yijing
Luo Guogang, a physician of the Qing dynasty, compiled a medical book titled Luoshi Huiyue Yijing (Mr. Luo's Collected Medical Mirrors). In this book he recorded a formula called "Da Bu Yin Tang" (Major Yin-Supplementing Decoction), which can be regarded as a derivative formula of Zhang Zhongjing's Jinkui Shenqi Wan (Golden Cabinet Kidney-Qi Pill) from the Han dynasty.
The composition of the formula is: Shu Di Huang (processed Rehmanniae Radix) 1 liang or 5 qian (15-30 g), Fu Zi (Aconiti Radix lateralis preparata) 3 qian (9 g), Rou Gui (Cinnamomi Cortex) 3 qian (9 g), Bai Zhu (Atractylodis Macrocephalae Rhizoma) 2.5 qian (7.5 g), Dang Gui (Angelicae Sinensis Radix) 3 qian (9 g), Fu Ling (Poria) 1 qian (3 g), Ren Shen (Ginseng Radix) 2 qian (6 g), Chao Gan Jiang (dry-fried Zingiberis Rhizoma) 1 qian (3 g), Zhi Gan Cao (honey-fried Glycyrrhizae Radix) 1 qian (3 g).
Luo Guogang used this formula to treat edema in patients for whom Shenqi Wan had failed. The formula was decocted in water for oral use. Luo noted that when treating edema with this formula, a large dose must be administered and it must be taken repeatedly to be effective.
Although Luo Guogang's "Da Bu Yin Tang" is named as a major yin-supplementing formula, it in fact contains a large amount of TCM yang-supporting herbs. Fu Zi, Rou Gui, Gan Jiang and Ren Shen in the formula all belong to yang-supporting drugs and are used in substantial dosages. Modern pharmacological studies show that most of these herbs are essentially cardiotonic agents. Therefore the most typical indication of Luo's formula should be cardiac edema in modern medicine; it is also suitable for edema due to impaired lymphatic drainage and for patients with thoracic or abdominal effusion complicated by heart failure.
Cardiac edema is a pathological condition in which circulatory venous pressure rises due to cardiac dysfunction (especially right-sided heart failure), causing abnormal accumulation of fluid in the interstitial spaces. The edema commonly appears in dependent areas such as the lower limbs. Patients show pitting edema on pressure over the lower legs, symmetrically on both sides, accompanied by heart-failure symptoms such as dyspnea (worse at night), fatigue and exertional shortness of breath. In most patients the edema begins at dependent sites such as the feet and ankles and gradually spreads upward to the calves and thighs; in severe cases it may involve the whole body.
Modern medicine usually treats such conditions by combining cardiotonic and diuretic agents while treating the primary disease. In Luo's formula, besides cardiotonic (yang-supporting) herbs such as Ren Shen, Fu Zi, Rou Gui and Gan Jiang, there are spleen-strengthening and water-disinhibiting herbs such as Bai Zhu and Fu Ling. This approach is consistent with modern medical thinking in treating cardiac edema and is quite scientific.
Luo's formula also includes Dang Gui, which invigorates and nourishes blood, and Shu Di Huang, which nourishes yin. Dang Gui promotes blood circulation. The role of Shu Di Huang in this formula is mainly to prevent excessive consumption of fluids by overusing yang-warming herbs such as Ren Shen, Fu Zi, Rou Gui and Gan Jiang, and water-disinhibiting herbs such as Bai Zhu and Fu Ling, which could otherwise damage yin and deplete fluids through spleen-strengthening and yang-supporting action. Such adjunctive herbs make the therapeutic effect of the formula more pronounced. From this perspective, Luo's medication strategy was very comprehensive.
Overall, the formula is well designed. Combining it with modern pathological knowledge allows us to apply it more precisely in clinical practice.