Emetic method in Shang Han Lun

Emetic method is one of the eight therapeutic methods in Shang Han Lun (Treatise on Cold Damager) written by Zhang Zhong-jing in the East Han Dynasty (3th century). It was the least used treatment method in Shang Han Lun, but it will not be complete if this method is not discussed in our series.
Emetics method makes the patient vomit so as to expel phlegm, undigested food, or toxic substances from the throat, the thoracic cavity or the stomach. The representative formula is Guadi San (Melon Stalk Powder).