畏、恶、忌与生地同。
甘、微温，微苦。入手足少阴、厥阴经血分。补真阴，填骨髓。凡阴虚火炎，水泛为痰，
津
枯无汗，烦躁不宁，耳目聋 ，神气散失，脂膏残薄，小水不利，大便不实，痿痹不仁，宿
滞不化，真阳不回等症，非此不疗。得乌梅，引入骨髓。得砂仁，纳气归阴。得炒干姜，治
产后血块。得丹皮，滋阴凉血。使玄参，消阴火。合当归，治胎痛。加牛膝，治胫股腹痛。
（血不足也。）和牡蛎，消阴火之痰。痰多，姜汁炒。行血，酒炒。润肠，人乳炒。纳气、
理气，砂仁炒。降火，童便煮。
摄精，
金樱子汁煮。补脾胃，炒炭存性。如煮熟未经蒸晒九次，寒凉之性未除，只算得心经凉剂，
损胃阳，伤胃气，不可妄用。若阴虚火动者，半生半熟之品，适得其宜。熟地味甘而滞，甘
为脾之所悦，虽滋肾实大益于土。经云∶味过于甘，肾气为土所掩，而不
上交于心，心亦不得下交于肾，肾气不冲而独沉，是有权而无衡也。人之忽然死者，正惟生
气不交，而独绝于内故尔。宜用辛凉者为之使，甘合辛而发散，则内气常通，心肾交结，自
无喘满之患。且肾气动而不滞，精升而化气，金气亦从水中生矣。肺气亦归于肾，补敛之剂
，何妨略加理气之味一二分，或五六分，俾补剂更为有力也。
Fear, aversion, and contraindications are the same as those of Shengdi Huang (Rehmanniae Radix).
Sweet, slightly warm, slightly bitter. Enters the blood aspect of the Shaoyin (Lesser Yin) and Jueyin (Terminal Yin) meridians of the hand and foot. It tonifies True Yin (Zhen Yin, the fundamental yin substance of the body) and fills the bone marrow. For conditions such as deficiency of yin with flaming fire, water overflowing to transform into phlegm, withered fluids leading to anhidrosis, restlessness and agitation, deafness and blindness, loss of spirit and qi, depletion of subcutaneous fat and muscle, difficult urination, loose stools, flaccidity and bi-syndrome with numbness, stagnation that fails to resolve, and failure of True Yang (Zhen Yang, the fundamental yang energy) to return, this herb is indispensable for treatment.
When combined with Wumei (Mume Fructus), it guides the effect into the bone marrow. When combined with Sharen (Amomi Fructus), it grasps qi and returns it to the yin. When combined with Chao Ganjiang (Fried Zingiberis Rhizoma), it treats postpartum blood stasis masses. When combined with Danpi (Moutan Cortex), it nourishes yin and cools blood. When used with Xuanshen (Scrophulariae Radix), it clears deficient fire. Combined with Danggui (Angelicae Sinensis Radix), it treats fetal pain. Added with Niuxi (Achyranthis Bidentatae Radix), it treats abdominal pain in the shins and thighs. (This is due to blood deficiency.) Combined with Muli (Ostrea Concha), it eliminates phlegm caused by deficient fire. If there is excessive phlegm, stir-fry with ginger juice. To promote blood circulation, stir-fry with wine. To moisten the intestines, stir-fry with human milk. To grasp qi and regulate qi, stir-fry with Amomi Fructus. To descend fire, decoct with child's urine. To secure essence, decoct with Cotoneastri Fructus juice. To tonify the spleen and stomach, char to carbon while preserving its nature.
If cooked but not subjected to nine steaming and nine sun-drying cycles, its cold and cool nature is not eliminated; it serves merely as a cooling agent for the Heart meridian, damaging Stomach Yang and injuring Stomach Qi, and should not be used recklessly. However, for patients with yin deficiency and moving fire, semi-raw and semi-cooked material is appropriate.
Shu Di Huang (Prepared Rehmanniae Radix) is sweet and cloying/stagnating. Sweetness is pleasing to the Spleen; although it nourishes the Kidney, it greatly benefits the Earth element. The Classics state: "If the flavor is overly sweet, Kidney Qi is obscured by Earth, preventing it from ascending to communicate with the Heart; consequently, the Heart cannot descend to communicate with the Kidney. Kidney Qi does not surge upward but sinks alone, possessing authority without balance." The reason for sudden death in humans is precisely that the vital Qi fails to communicate, becoming isolated and severed within.
It is advisable to use acrid and cool substances as guiding agents. Combining sweet with acrid promotes dispersion, ensuring internal Qi remains unobstructed, allowing Heart and Kidney to interact, thereby naturally avoiding disorders of panting and fullness. Furthermore, when Kidney Qi moves without stagnation, essence ascends and transforms into Qi, and Metal Qi also arises from Water. Lung Qi returns to the Kidney. Therefore, in tonifying and astringent formulas, it is acceptable to add a small amount (one or two fen, or five or six fen) of qi-regulating herbs, making the tonifying formula more effective.