Digu Pi Tang (Cortex Lycii Decoction) for Lung-Heat Dyspnea and Shortness of Breath

In the Shengji Zonglu (General Records of Holy-Imperial Benevolence) there is a formula called “Digu Pi Tang” (Cortex Lycii Decoction), composed of: Cortex Lycii (Digu Pi) 5 liang (150 g), Baiqian (Rhizoma Cynanchi Stauntonii) 2 liang (60 g), raw Gypsum (Sheng Shigao, ground into powder) 6 liang (180 g), Armeniaca Semen (Xingren, peeled, tip and double kernels removed, stir-fried) 3 liang (90 g), and Cortex Mori (Sangbaipi, filed) 4 liang (120 g).

The above herbs are ground together into a coarse powder. Each time take 6 qian (18 g), add 300 ml of water and 10 bamboo leaves, decoct down to half, strain off the dregs, and take warm, twice daily. This formula clears lung heat and calms dyspnea; it is indicated for excess heat in the lung with wheezing and counterflow qi, fullness in the chest, and labored upright breathing with shortness of breath. These symptoms are mostly seen in patients who develop pleural effusion after a pulmonary infection.

This formula is essentially a combination of Ma Xing Shi Gan Tang (Ephedra, Apricot Kernel, Gypsum and Licorice Decoction) and Xie Bai San (White-Dispersing Powder), with modifications. Ma Xing Shi Gan Tang comes from the Shanghan Lun (Treatise on Cold Damage) and consists of Herba Ephedrae, Armeniaca Semen, Gypsum, and Radix Glycyrrhizae preparata; it is the representative formula for cough and wheezing when an exterior pathogen has not been resolved and pathogenic heat congests the lung. The present formula treats excess lung heat but without an exterior pattern (no aversion to cold or fever), so Ephedra is omitted. Xie Bai San consists of Cortex Lycii, Cortex Mori, rice, and Licorice; it is also a representative formula for lung-heat cough and wheezing, indicated for wheezing and cough, steaming heat of the skin (worse in the afternoon), a red tongue with yellow coating, and a rapid thin pulse. In patients with chest fullness, herbs such as rice and Licorice—whose cloying, greasy nature obstructs the diaphragm—are appropriately removed. Baiqian descends qi, stops cough, and calms wheezing; adding it strengthens the formula’s power to arrest cough, calm wheezing, and descend counterflow. Bamboo leaves clear and drain damp-heat and conduct heat downward, opening an exit for the pathogen. With this combination, the action on lung-heat cough and wheezing is further strengthened.

The dosage above is rather small; if a patient’s symptoms are acute, a decoction should be used. The adult daily dose is as follows: Cortex Lycii 15 g, Baiqian 6 g, raw Gypsum 18 g (decoct first), Armeniaca Semen 9 g, Cortex Mori 12 g, bamboo leaves 6 g. Decoct with 2 bowls of water down to 1 bowl; take 1 dose daily, divided into 2 portions. Severe patients may take 2–3 doses daily, divided into 4–6 portions. While taking this formula, the diet should consist mainly of cooked and vegetarian foods; meat may be gradually added only after the heat has subsided and the wheezing has calmed.