Kidney Essence Running Low and Always “On Fire”? Why Prepared Rehmannia (Shu Di Huang) Tonifies Kidney Essence So Well — the Ming Master Doctor Zhang Jingyue, Nicknamed “Zhang the Prepared Rehmannia”, Explained It All

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Medical terms for this condition: kidney essence (shen jing) · true yin (zhen yin) · deficiency fire (xu huo) · dragon-thunder fire blazing upward (long lei zhi huo shang ben) · blood and sweat share the same source (xue han tong yuan) · without yin, no sweat can form (wu yin bu zuo han) · essence transforms into qi (jing hua qi) · tonifying qi mainly with ginseng, tonifying blood mainly with prepared rehmannia · Jin Gui Shen Qi Wan (Kidney Qi Pill from the Golden Cabinet) · yin within yang, yang within yin · after forty, yin is half gone (ren guo si shi, yin qi zi ban) · Yin Huo Tang (Fire-Drawing Decoction)

💬 Note from Doctor Luo: Dear friends, good morning everyone. Today we talk about Doctor Zhang Jingyue’s medication experience. After listening to so many of Zhang Jingyue’s case studies, you will have noticed that his academic thinking places enormous weight on one thing — the kidney. He emphasized kidney essence especially, calling it true yin (zhen yin). Tonifying true yin, tonifying kidney essence, and using it to treat all kinds of illness — this is a very important part of his academic system. The Ming-dynasty doctors like Zhang Jingyue and Chen Shiduo developed the treatment of kidney essence to what can be called the extreme, and their theoretical system was already complete.

Opening: this famous doctor’s nickname was “Zhang the Prepared Rehmannia”

Many illnesses today are what we call “upper-jiao fire” — fire in the head and face: red eyes, sore throat, headaches, all kinds of fire in the three burners. Many people assume fire must be cleared, but what Doctor Zhang Jingyue saw was often deficiency fire — the dragon-thunder fire (long lei zhi huo) blazing upward. Doctor Xue Lizhai talked a lot about the deficiency fire caused by yang deficiency, spleen-kidney yang deficiency; what Zhang Jingyue talked about was deficiency fire rising from insufficient kidney essence.

💬 Note from Doctor Luo: In Zhang Jingyue’s treatment, what herb did he use most often? Prepared rehmannia (shu di huang). He was exceptionally skilled with it. If you study Zhang Jingyue and master prepared rehmannia and ginseng, I think you will have most of tonifying deficiency in hand — it is extremely effective. Especially if you use prepared rehmannia well, you will be truly formidable. That is why Zhang Jingyue’s nickname was “Zhang Shudi” — “Zhang the Prepared Rehmannia” — because he used it so well.

What exactly is so good about prepared rehmannia? Zhang Jingyue explained it in one breath

In his medical books, he discussed prepared rehmannia from beginning to end. Zhang Jingyue said: prepared rehmannia is sweet with a touch of bitter, thick in substance and thin in qi, and it sinks downward — it is “yin with yang inside,” a herb in which yin and yang are joined in one body. The materia medica says it enters the jueyin and shaoyin channels of the hands and feet, and greatly tonifies blood decline, nourishes kidney water, fills the marrow, and benefits true yin (zhen yin).

💬 Note from Doctor Luo: There is one phrase in these lines especially worth noting — “fill the marrow.” The bone marrow is an extremely vital part of the body, yet we rarely talk about it. Later, the old master Doctor Zhao Shaoqin, treating kidney disease, said that warm disease has the four levels of wei qi, ying qi, and blood — but beyond blood there is another level, the “marrow division (sui fen).” When pathogenic qi enters the marrow division, the illness is always very severe; most blood diseases and the like are serious conditions. So who governs this marrow division? The kidneys govern the bones and generate marrow; the brain is the sea of marrow (shen zhu gu sheng sui, nao wei sui hai) — this whole chain is connected: brain, marrow, and kidneys are all linked. Prepared rehmannia can fill the marrow precisely because it tonifies the kidneys so well, and it has an excellent nourishing effect on the marrow.

Grown in Wen County, Jiaozuo, Henan: a treasure from the fertile soil of the Central Plain

Some people worry: prepared rehmannia is rich and cloying; eat it and it obstructs the spleen and stomach — people with weak spleen and stomach cannot tolerate it. What did Zhang Jingyue say? He said prepared rehmannia is produced in the fertile soil of the Central Plain (zhong zhou wo tu zhi xiang) — Wen County, Jiaozuo, Henan, called Huaiqing Prefecture (Huai Qing Fu) in ancient times, growing in the same fields as the Huai yam (lu tu yam).

💬 Note from Doctor Luo: The ancients held that the center belongs to Earth, and the Central Plain receives the earth qi most abundantly and purely. When prepared rehmannia arrives, its color is yellow — yellow is the color of Earth (se huang, tu zhi se ye); its taste is sweet — sweet is the taste of Earth (wei gan, tu zhi wei ye). It carries the qi of Earth, so if anyone tells you it cannot treat spleen and stomach disorders, I do not believe it. Raw rehmannia is cool in nature, and the spleen and stomach like warmth, so people with insufficient spleen yang should use it cautiously; but once prepared, it is neutral in nature, bearing the virtue of supreme yin, pure in flavor and qi, and can tonify the true yin of the five organs. Moreover, what it treats is precisely the “blood-rich organs” — the spleen and stomach channels are abundant in both qi and blood — so prepared rehmannia can certainly treat the spleen and stomach.

Ginseng paired with prepared rehmannia: one above, one below; one qi, one blood

Zhang Jingyue also discussed the coordination of tonifying qi and tonifying blood. Why do we have life? Because of qi and blood. Qi governs yang and movement; blood governs yin and stillness. To tonify qi, ginseng is the lead, with astragalus and atractylodes assisting; to tonify blood, prepared rehmannia is the lead, with chuanxiong and angelica assisting.

💬 Note from Doctor Luo: Therefore, whenever essence-qi yang deficiency appears, ginseng is indispensable; whenever true yin and blood are deficient, prepared rehmannia is indispensable. Ginseng has the power of moving and transforming (jian yun zhi gong) — it makes the body run fast; prepared rehmannia bears the virtue of quiet reverence (jing shun zhi de) — it can sit serenely in command. This one yin and one yang, mutually exterior and interior, one form and one qi, with upright and centered natures — these two herbs are irreplaceable. And ginseng tonifies the upper part (lung qi, heart qi), while prepared rehmannia tonifies the lower part (liver and kidney, chiefly the kidney) — one above and one below, one qi and one blood. But tracing back to the root: kidney essence is the core. Kidney essence contains yin and yang and transforms to generate yin and yang. When tonifying essence and directing it toward qi, add ginseng and wolfberry; when directing it toward nourishing blood, add prepared rehmannia, angelica, and chuanxiong. The root of qi and blood is kidney essence — you must hold this understanding firmly.

When kidney essence runs low, what happens? Zhang Jingyue listed a long string of signs

Zhang Jingyue said that whenever true yin is depleted (kidney essence deficiency), what symptoms appear? Fever — deficiency heat rising; headache — again heat rising; scorching thirst and throat blockage (jiao ke, hou bi) — sores growing in the throat; coughing, profuse phlegm, wheezing; when the spleen and kidney are cold and rebellious, vomiting; or deficiency fire carries the blood up to the mouth and nose, bleeding from the mouth and nose; or water flooding the skin (edema); or yin deficiency diarrhea; and also floating yang with agitation and mania, suddenly collapsing from deficiency, and scattered spirit (shen san) — the spirit dispersing and the mind unable to gather itself.

💬 Note from Doctor Luo: Let me say a fair word here: in practice, Zhang Jingyue applied the treatment of kidney essence extremely skillfully and precisely, but conceptually he was a little fuzzy — he often discussed “yin” and “true yin” (kidney essence) together as one thing. Speaking of them together is not exactly wrong, but it is not helpful for distinguishing them. Now that we separate them, it becomes clearer. The ancients achieved it in practice and touched on it in theory; we just need to sort out the distinction.

The seven uses of prepared rehmannia: gathering the spirit, lowering fire, settling agitation, relaxing urgency, controlling water, returning to the origin, and thickening the stomach and intestines

Zhang Jingyue laid out the marvels of prepared rehmannia from seven angles:

When yin is deficient and the spirit scatters, nothing but rehmannia’s holding power can gather it. A scattered spirit means the inner core can no longer contain itself. Fill the essence of the five organs, and the spirits of the five organs return. So many problems of the spirit and the emotions truly need the essence tonified to call the spirit back.
When yin is deficient and fire rises, nothing but rehmannia’s weight can lower it. Deficiency fire rises; rehmannia is heavy in flavor and moves downward, pressing the fire down.
When yin is deficient and there is agitation, nothing but rehmannia’s stillness can settle it. When kidney essence is insufficient and the dragon-thunder fire rushes upward, rehmannia can hold it still.
When yin is deficient and there is fierce urgency, nothing but rehmannia’s sweetness can relax it. When liver fire flares up and the illness comes on violently, rehmannia’s sweet, gentle quality softens it.
When yin is deficient and water evil floods out of control, without rehmannia how could it be restrained? When kidney essence is insufficient and both yin and yang are depleted, water evil runs wild; without rehmannia, who can control it?
When yin is deficient and true qi is being lost, without rehmannia how could it return to the origin? Rehmannia can draw the scattered true qi back home.
When yin is deficient and essence and blood are both damaged, the fatty substance worn thin, without rehmannia how could the stomach and intestines be thickened? When kidney essence is insufficient, qi and blood are depleted, the subtle nutritious matter has been consumed away; without tonifying kidney essence the spleen and stomach stay weak, and nutrients cannot be retained.

💬 Note from Doctor Luo: And there is one most mysterious point — rehmannia combined with dispersing herbs — how can that possibly induce sweat? Why? Because sweat is transformed from blood, and without yin, no sweat can form (wu yin bu zuo han). If the yin substance in your body is insufficient and your blood is insufficient, sweat cannot form either — blood and sweat share the same source (xue han tong yuan). Use rehmannia to tonify kidney essence and kidney yin; once the yin fluids are sufficient and the blood is sufficient, then sweat can come out. During the epidemic I talked about people who simply could not sweat: it was very hot, they wore thick clothes and sat in the sun trying to sweat, sunbathing at noon — not a single drop of sweat, and taking medicine produced no sweat either. That is upright qi deficiency. Give them rehmannia, ginseng, and the like, and the sweat comes gushing out — this I have seen with my own eyes. When upright qi recovers and fluids are sufficient, sweat can come out and the pathogenic qi can retreat.

Paired with warming herbs it restores yang: the pioneer of using two to three liang at a time

Prepared rehmannia combined with warming agents can restore yang — add a little yang-warming medicine, and you can call the yang back. When kidney essence is depleted, some cases develop toward kidney-yin deficiency, others toward kidney-yang deficiency. Use rehmannia to tonify kidney essence, add a little warming medicine, and the yang is promptly recovered.

💬 Note from Doctor Luo: Some people are afraid that rehmannia is rich and cloying, and dare not use it in large amounts. In fact, rehmannia rarely works unless used in generous doses — look at how large the rehmannia dose is in the Kidney Qi Pill. Zhang Jingyue used rehmannia at two to three liang (about 60–90 g) at a time, paired with just a little cinnamon and aconite — this pioneered the large-dose use of prepared rehmannia, and its source is the thinking of Zhang Zhongjing’s Eight-Ingredient Pill (the Jin Gui Shen Qi Wan, Kidney Qi Pill from the Golden Cabinet). He said yin and yang generate each other: without yin, yang cannot be born; without yang, yin cannot arise. The Inner Classic says “essence transforms into qi (jing hua qi)” — kidney essence generates kidney qi, and kidney qi then transforms to produce yin and yang. That is how it works.

Zhang Jingyue also discussed the processing of prepared rehmannia: some process it with ginger juice (for especially cold conditions), with amomum (sha ren) (for abdominal distension), with wine (for channel and network stasis), and so on. These methods can be used, but if used badly, they are merely gilding the lily.

💬 Note from Doctor Luo: By the Qing dynasty, everyone basically did this — when treating the wealthy, if you did not fuss and fiddle, they felt you were not being conscientious. So as soon as rehmannia was prescribed, it had to be stir-fried with amomum and so on — always processed, so you felt, “look how meticulous I am.” My own view: some cases genuinely call for it; some are simply the habit of treating rich patients — you fuss a little to reassure them. Also, when some people tonify yin, they always want to add herbs that drain dampness outward. Zhang Jingyue’s view was there is no need — tonify the yin sufficiently and the upright qi recovers; the body will expel the water by itself. Of course, both approaches can work.

Doctor Luo’s health advice: make prepared rehmannia your kitchen companion — stew it in soup once a week

Zhang Jingyue’s use of prepared rehmannia stands basically at the summit of tonifying deficiency — just as the later Doctor Zhang Xichun had his raw gypsum and Huai yam, every physician has a uniquely deep understanding of the herbs he excels at. We just need to learn it.

💬 Note from Doctor Luo: My earlier view was: after forty, yin is half gone (ren guo si shi, yin qi zi ban) — from the Inner Classic. For health preservation in middle age, drink rehmannia soup once or twice a week — put a small piece of prepared rehmannia into the soup with a slice of cinnamon (a small slice is enough) and stew it. Any meat soup will do, even pork soup; once or twice a week, it can only do the body good. Because human essence is bound to be depleted — thinking every day, staying up late, burning the candle at both ends, indulgence — all of it depletes you. But now I find that waiting until 40 to tonify is already too late for many people — they were depleted long ago. How many young people have I seen with sore throats, swollen eyes, trigeminal neuralgia, headaches, swollen throats, mouth ulcers — the fire of the upper jiao blazing up. How do you fix it? Prepared rehmannia with a little cinnamon — it goes away at once; one dose of the Fire-Drawing Decoction (Yin Huo Tang) brings it right down. Look at how modern people stay up late, indulging and over-thinking; too many young people have depleted kidney essence. It needs to be replenished — and once replenished, learn to restrain yourself, stop the dissipation.

Finally, Doctor Luo Dalun says: the marvels of prepared rehmannia truly cannot be fully described. Kidney essence is the root of the body — if you can understand this when regulating your health, you have truly found the foundation of longevity. In daily life, treat prepared rehmannia as a “companion” — like the scallion, ginger, and garlic in your kitchen. Keep some at home; 10–20 g stewed in soup once a week will certainly do you good. But do not drink it every single day — 60 g every day, and anyone with a weak spleen and stomach will end up with loose stools.

💬 Note from Doctor Luo: In Zhang Jingyue’s prescribing, prepared rehmannia ranks first and ginseng second. Tomorrow we will talk about how Zhang Jingyue used ginseng. Master these two herbs and you have grasped a large part of tonifying deficiency.

Compiled from Doctor Luo Dalun’s commentary on Doctor Zhang Jingyue’s medication experience; content based on the Complete Works of Jingyue (Jing Yue Quan Shu).