Dong, 27 years old, a worker. Suffering from a cough for more than three months, tried various Chinese and Western medicines without effect. Experienced throat itch, copious phlegm, clear and thin like water, mixed with frothy bubbles. Tongue and pulse showed no signs of heat, with no other discomforts. Tentatively prescribed the original formula of Minor Green-Blue Dragon Decoction:
Ephedra 6g, Cinnamon Twig 10g, Pro Formula Pinellia 15g, Asarum 3g, Schisandra Fruit 6g, Peony Root, Dried Ginger, each 10g, Prepared Liquorice Root 6g
. One dose reduced the cough, and three doses completely cured it.

The syndrome of Minor Green-Blue Dragon Decoction is characterized by external cold pathogens and internal retention of water, indicating a condition of cold both inside and outside. The structure of Minor Green-Blue Dragon Decoction is roughly divided into three groups: the first group of herbs, Ephedra and Cinnamon Twig, releases the exterior and dissipates cold (as stated in the original text of "cold-damage disease theory": "the exterior of cold-damage disease is not resolved"); the second group uses Dried Ginger and Pinellia to eliminate water retention (as stated in the original text of "cold-damage disease theory": "there is water qi below the heart"); the third group includes Peony Root and Schisandra Fruit, which are sweet and sour to moderate the harshness of the medicinal properties, making them a controlled force. The inclusion of Asarum in the formula has a profound meaning: one aspect is to assist Ephedra and Cinnamon Twig in releasing the exterior, another is to help Ginger and Pinellia transform the retained water, and the sour astringency of Schisandra Fruit, paired with the acrid dispersion of Asarum, aims to restore the normal ascending and descending functions of the lungs, thereby stopping the cough, which is the third layer of meaning.