Actually, both medicines can be used among kidney deficiency (yin and yang). This is because patients with kidney deficiency are also deficient in liver and blood, and have heavy internal heat (yin deficiency). External cold is also heavy (yang deficiency). In terms of medicinal properties. Sheng Di is cold. It nourishes Yin and clears heat, and is mainly used in cases of Yin deficiency of the Liver and Kidneys. The ripe earth is warm, nourishes blood and benefits the liver, and is used to replenish the deficiency of liver and blood. Therefore, in the clinical evidence must be realized by the heart. As the saying goes: the principle of the medical door to the micro-hysteria, the heart of the heart to have mediation, looking, hearing, questioning and cutting four things, the lack of a time is not ready for the whole.