Dan (瘅) figuratively means heat in traditional Chinese medicine. In modern medicine, diabetes in its early and middle stages can be divided into the syndrome of spleen heat and the syndrome of pure-heat dispersionthirst, in which the core pathogenesis of the spleen heat syndrome is the flatulence and endogenous heat, while the core pathogenesis of the syndrome of pure-heat dispersion-thirst is the liver depression, spleen deficiency and stomach heat. At these two stages of the disease, clearing heat is viewed as the fundamental treatment for either syndrome.Peony root, fresh rehmannia root and amur cork-tree are commonly used in a minor prescription by Academician Tong Xiaolin, referred to as Liangcui Yin, for clearing heat, cooling blood and reducing blood sugar. The prescription is mostly used in the treatment of diabetes with the symptoms of heat depression transforming into fire, burning stomach yin and consuming blood, fier-heat extremely intense and rampant. Peony root can clear heat, cool blood, and disperse blood stasis to protect collaterals. Fresh rehmannia root, whose flavour and nature is sweet and cold, can cool blood and nourish stomach yin. Amur cork-tree, whose flavour and nature is bitter and cold, can clear fire and reduce blood sugar. Bitter-cold amur cork-tree clears the stomach fire, while sweet-cold fresh rehmannia root nourishes the stomach yin, clearing heat and cooling blood, preventing the fire poison from consuming blood, also bearing the meaning of "treating collaterals in the early stage, clearing collaterals in the whole process" . According to the heat intensity, the dosage range of the three herbs in the prescription is usually 15-30 g in clinical use. If the fire in either syndrome is intense and rampant, the dosage usually starts at 30 g.