Elderly Fever, Confusion and a Shrinking Tongue? Doctor Zhang Xichun’s Prepared Rehmannia for Kidney Essence Deficiency in Febrile Disease
Opening: picking up yesterday’s thread — today is another "prepared rehmannia special"
Doctor Luo Dalun says: yesterday we told the story of how Doctor Zhang Xichun saved a dying maidservant with prepared rehmannia (shu di huang). Today let’s keep going — how exactly did Doctor Zhang Xichun use this herb? Last time, he paired prepared rehmannia with dried Chinese yam slices. This time, the patient was an elderly woman from a neighboring village, and her condition was even more dangerous than the last.
💬 Note from Doctor Luo: We’ll call it "prepared rehmannia" for short (in Chinese, shu di). Doctor Zhang Xichun rarely used it alone — it was the old partner of dried yam slices. You’ll see that pairing with your own eyes in today’s case.
Who was the patient? A woman in her seventies from Longtan village, struck down in summer
The patient was an elderly woman surnamed Zhang, who lived in a village called Longtan in the neighboring area of Doctor Zhang Xichun. She was over seventy years old, and her health had never been robust. And the illness struck precisely in summer — the season of the year when yang qi is at its peak and the weather is hottest. Suddenly she came down with a febrile disease (wen bing).
💬 Note from Doctor Luo: What is a febrile disease (wen bing)? It is an externally contracted heat disease — the kind of illness that starts with fever from the very beginning, along with a sore, swollen throat and a full picture of heat. Catching a febrile disease in summer is especially dangerous for the elderly.
How sick did she get? Five or six days of unrelenting high fever, and she was already confused
The old woman’s illness came on fiercely. Within five or six days — just a few short days — she began with body heat and a high fever; then came dryness and scorching thirst, her mouth parched, thirsty and constantly wanting to drink; and after that, her consciousness clouded — her mind was failing, she grew confused, drifting in and out of a dazed state.
The family took one look and knew this was no small matter. They hurriedly sent for Doctor Zhang Xichun. When he arrived, what did he do first? He looked at the tongue.
💬 Note from Doctor Luo: Everyone, take note: Doctor Zhang Xichun did value tongue diagnosis — he simply didn’t write it down in many of his case records. In this case he examined the tongue with unusual care, because the tongue revealed an enormous amount of information.
One look at the tongue: no coating, the surface black and shrinking — a danger signal
Doctor Zhang Xichun looked at her tongue: there was no coating — it was as if all the coating had vanished. What does the absence of coating mean? When a person is yin deficient (yin xu) — short of fluids — the tongue tends to lose its coating, or the coating becomes extremely thin, and the tongue is often red.
This old woman’s tongue was even more troublesome — the membrane of the tongue showed black in several places, patches of black scattered here and there, dry, and the tongue surface kept shrinking back.
💬 Note from Doctor Luo: In Chinese medicine, it is generally held that when a person is so ill that the tongue shrinks back, the condition is critical — extremely serious. The moment he saw this tongue, Doctor Zhang Xichun’s heart tightened.
One touch of the pulse: thin, rapid and weak — Doctor Zhang knew what he was dealing with
Then he took the pulse: thin, rapid and weak (xi shu wu li) — very fine, beating fast, and without strength. What does that mean? Yin deficiency. In general, a yin-deficient person’s pulse beats especially fast.
💬 Note from Doctor Luo: A rapid pulse (shu mai) has two common causes: one is yin deficiency, the other is great depletion of kidney essence (shen jing). This old woman had fever, no tongue coating, and a shrinking tongue — yin deficiency was beyond doubt. But at over seventy years old, an underlying depletion of kidney essence was equally certain. The two problems were stacked on top of each other — which is exactly why the illness was so severe.
Science corner: what is yin deficiency? What is kidney essence deficiency? Are they the same thing?
Here Doctor Luo Dalun takes Doctor Zhang Xichun’s case and carefully unpacks both concepts.
Yin deficiency means the body’s fluids are insufficient — the fluids and essence that moisten and nourish the body run low. What does a yin-deficient person look like? The tongue turns red — the redder the tongue, potentially the more serious; the coating is very thin or absent; the pulse beats fast and thin (xi shu); the eyes are very dry; there is thirst with a preference for cold drinks; five-center heat (wu xin fan re) — heat in the palms, soles and chest with inner restlessness; night sweats (dao han) — sweating the moment sleep comes; and a tendency to bone-steaming tidal heat (gu zheng chao re) — gu zheng is heat radiating outward from deep inside the body, so that when you touch the arm the heat slowly builds and pushes out from within; chao re is fever that comes and goes at set times like the tide, the whole body heating up at the same hour each day.
💬 Note from Doctor Luo: There are many causes of yin deficiency: people who love spicy food tend toward it; people who deplete themselves in various ways — for instance those who stay up late — tend toward it; and people of advanced age tend toward it as well.
And what is kidney essence (shen jing)? Doctor Luo Dalun explains: kidney essence is inherited from one’s parents — the congenital essence is sealed and stored in the kidneys; combined with the fine substances absorbed from food after birth, plus the clear, light qi drawn in through breathing, it finally forms kidney essence, sealed in the kidneys. Kidney essence is the original driving force of human growth. As the years pass and the body endures all kinds of wear and tear, kidney essence is gradually depleted; excessive, unrestrained sexual activity and exhausting the mind day after day with too much thinking both consume it.
People with insufficient kidney essence tend to age prematurely: growth and development lag; they often suffer dizziness and tinnitus, weak sore lower back and knees, and declining sexual function; spirit fatigue and poor memory — low energy and a forgetful mind; excessive nighttime urination — getting up again and again at night, some people seven or eight times a night, with dribbling after urination; graying and falling hair too early, decaying and loose teeth too early.
💬 Note from Doctor Luo: Kidney essence deficiency and kidney yin deficiency usually appear together, though they are slightly different. This old woman was advanced in years, so kidney essence deficiency was unavoidable; and when essence is insufficient, yin is likely insufficient too — the two problems were layered on top of each other, which is why the illness was so heavy.
Doctor Zhang Xichun’s hesitation: the patient was too old — after long deliberation, he wrote two formulas at once
Facing a woman over seventy, burning with fever, confused, her tongue shrinking back — Doctor Zhang Xichun did not rush to write a prescription. He deliberated again and again. Not because he was indecisive, but because the patient’s age was so advanced that every ingredient had to be chosen with the utmost care. After thinking it over for a long time, he finally wrote out two formulas at once.
💬 Note from Doctor Luo: Why two formulas? One was to bring down the fever and clear the pathogen, the other to replenish essence and support the upright qi — both sides had to be covered. The old woman’s illness was "residual heat pathogen with greatly depleted upright qi" (xie re wei jin, zheng qi da xu): clearing heat alone and the old woman couldn’t hold on; tonifying deficiency alone and the fever would never come down.
The prescriptions revealed: White Tiger Plus Ginseng Decoction (yam instead of rice) + 2 liang of prepared rehmannia with yam, wolfberry, donkey-hide gelatin and egg yolks
The first formula was the White Tiger Plus Ginseng Decoction (Bai Hu Jia Renshen Tang), with Chinese yam replacing the rice (jing mi). White Tiger Decoction is the classic formula of Zhang Zhongjing for clearing blazing heat in the yangming channel. Doctor Zhang Xichun added ginseng to it, to tonify qi and nourish yin; and he swapped the rice in the formula for Chinese yam — this was Doctor Zhang Xichun’s invention, using yam in place of rice to protect stomach qi and replenish spleen yin.
The second formula was prepared rehmannia’s showcase: prepared rehmannia (shu di huang) 2 liang (about 60 g), raw Chinese yam / dried yam slices (sheng shan yao) 1 liang (about 30 g), wolfberry (gou qi zi) 1 liang (about 30 g), donkey-hide gelatin (e jiao) 5 qian (about 15 g) — all yin-nourishing medicines. After decocting, four raw egg yolks (sheng ji zi huang) were stirred into the warm soup, and the patient drank it all.
💬 Note from Doctor Luo: You see, Doctor Zhang Xichun used prepared rehmannia and dried yam slices in a fixed proportion — usually 2 liang of prepared rehmannia paired with 1 liang of dried yam slices. He did this in many of his formulas; it was his hard-won experience. Add wolfberry, donkey-hide gelatin, and four raw egg yolks, and the power to nourish yin and replenish essence is complete.
The outcome: two formulas taken alternately, sipped slowly — one course of medicine, and she recovered
Both formulas were each decocted into one large bowl, then given to the patient — sipped slowly, a little at a time, the two decoctions taken alternately while warm. What was the result? After one full course of the medicine, the old woman’s illness was cured.
💬 Note from Doctor Luo: Just listen to that — what a serious illness this was! Doctor Zhang Xichun often cured extremely serious diseases in a very short time — his use of medicine was so precise that the condition was brought under control almost immediately. That was his mastery. It is why, during the Republican era, Doctor Zhang Xichun was honored as one of the most influential figures in Chinese medicine.
What to take away: what does this case teach us?
Today’s case tells us: what is kidney essence deficiency (shen jing bu zu)? Prepared rehmannia has the power to replenish kidney essence — for anyone with depleted kidney essence, prepared rehmannia is the one herb you cannot avoid. Doctor Luo Dalun says: tomorrow we’ll continue — when kidney essence is depleted, how did Doctor Zhang Xichun keep using prepared rehmannia next?
💬 Note from Doctor Luo: Keep an eye out for these signals in your elderly family members: frequent nighttime urination, forgetfulness, weak sore lower back and knees, premature graying of hair and loosening of teeth — any of these may point to kidney essence deficiency. For replenishing essence, prepared rehmannia is the most important herb of all. But how to use it, and what to pair it with, must be decided through proper pattern differentiation — don’t grab herbs and self-medicate.
Based on Doctor Luo Dalun’s explanations of Doctor Zhang Xichun’s case records. The case is from Records of Chinese Medicine with Reference to Western Medicine (Yixue Zhongzhong Canxi Lu), published in installments between 1918 and 1934.