Di Huang is mainly divided into Raw Di Huang and Cooked Di Huang. Raw Dihuang is generally used to nourish yin, nourish blood, nourish yin and generate fluid. It can be used to clear away heat and nourish yin when there is a deficiency of yin and fire, or when there is a lack of fluid, resulting in dry mouth and irritable heat. Radix Rehmanniae Praeparata (熟地黄) is mainly used to nourish Blood, nourish Yin and fill in the marrow. It is generally used in cases of yin deficiency and exuberance caused by deficiency of kidney essence, or deficiency of the liver and kidney. Generally, you can see that Chinese medicines such as Zuo Gui Drink, Zuo Gui Pill, Yu Gui Drink, Yu Gui Pill, which nourish kidney essence, nourish kidney yin, or calmly nourish kidney qi, nourish kidney yang and so on, all of them contain Radix Rehmanniae Praeparata, which is used for nourishing the kidneys and filling in the essence of the marrow. Therefore, when seeking yang in yin, or yin in yang, and when tonifying kidney qi in an even manner, cooked Di Huang is usually put in, and this is the difference between raw Di Huang and cooked Di Huang.