Woodcut illustration from an edition of 1833 (13th year of Daoguang reign period of Qing dynasty). The image and text give an account of the principles of diseases treated with Great Blue/Green Dragon decoction, and the therapeutic effects of the individual ingredients of this remedy. Great Blue/Green Dragon decoction is used to treat dual wind-cold damage to the taiyang channel, when nutrient and defensive Qi are both impaired,and the patient is distressed and restless (fanzao) and does not sweat. The external malignance in the taiyang channel stagnates and turns to heat, which enters the interior of the body, manifesting as distress and restlessness. Gypsum, being cold and pungent in sapor, is used to clear the heat and still the distress and restlessness. When wind-cold malign Qi stagnates in the muscles and external stratum of the body, this manifests as absence of sweating. Ephedra (mahuang), apricot kernel (xingren) and cassia twig, which are pungent and warm and have a dispersing effect, are used to release the external malignance.