Shuangyu Powder: Treating Lung-Heat Cough

Shuangyu San (Double Jade Powder) originates from Suwen Bingqi Yi Baoming Ji (Plain Questions on Pathogenesis and Qi-Activity: Life-Preserving Collection), the celebrated work of Liu Wansu, a famous physician of the Jin-Yuan Yi Shui school. Liu Wansu was the foremost of the four great Jin-Yuan masters; he proposed the famous "fire-heat theory" and favored cold-cooling herbs in treating disease.

Shuangyu San is a small formula composed of typical cold-cooling medicines. Its composition is Hanshuishi (Glauber's salt, gypsum rubrum) and Sheng Shigao (Raw Gypsum), each in equal amounts, ground together into fine powder. Each time take 3 qian (9 g) of the powder, mixed and taken with ginseng decocted after meals. Shuangyu San clears and drains lung heat. It is indicated for internal accumulation of phlegm-heat: cough with abundant phlegm, vexation and thirst, and headache. These symptoms resemble those of modern acute respiratory infection.

Both Hanshuishi and Raw Gypsum in this formula are sulfates; in TCM they are strongly cold in nature, both with the action of clearing heat and downbearing fire. Used together, their heat-clearing and fire-downbearing strength is greater. In clinical practice, Hanshuishi and Raw Gypsum indeed have a relatively rapid anti-inflammatory and antibacterial action and can treat respiratory infection, and the effect is quite fast.

But as later critics pointed out, such bitter-cold medicines easily damage the spleen and stomach. Sulfate mineral drugs in the stomach form sulfuric acid with the hydrogen ions of gastric juice, which is harmful to the digestive-tract mucosa. Some patients develop nausea, vomiting, diarrhea, or drug rash after taking them. Hence this formula should not be used in large doses or for long periods.