A Boil on the Back, Swollen Like a Plate and Hard as Stone?
Search terms: boil on the back / sores on the back / fever / bowel movements blocked / cannot pass stool / distended belly / bright red face / no sweating
Medical terms for this condition: cold damage · Yangming fu excess · skin sores (back boil) · Da Cheng Qi Tang pattern
Opening scene: the illness was already cured — so why did the doctor say, “You have planted a land mine for yourself”?
Today we continue with the case records of Doctor Xu Shuwei, the great master of classical formulas during the Northern–Southern Song transition. Known as “Scholar Xu” (Xu Xueshi), he studied Zhang Zhongjing’s Shang Han Lun (Treatise on Cold Damage) with extraordinary devotion and excelled at using its classical formulas. He wrote Shang Han Jiu Shi Lun (Ninety Discussions on Cold Damage) — the earliest surviving medical casebook in Chinese history — recording each case with its own discussion, remembering every patient he treated with precision.
This case is especially interesting: the patient’s illness was clearly cured — yet Doctor Xu Shuwei sighed right in front of everyone: “You are only seeking comfort for the moment, and storing up a disaster for later!” Half a month later, the disaster really did explode: a great boil swelled up on the patient’s back — swollen like a plate, hard as stone.
💬 Note from Doctor Luo: This case teaches one of the most important principles in Chinese medicine — treatment must pull out the root; you must never leave the pathogen behind. The illness being gone does not mean the pathogen has been cleared. If you take the easy road today and fail to purge the toxin out, it will erupt sooner or later. This lesson applies just as much today.
Who was the patient? An official named Li Chen, whose body was “blocked inside and out”
The patient was Li Chen (李琛), an official. He contracted cold damage (shang han) — in ancient times, any external-contraction febrile illness was called shang han; it is not quite the same as today’s “caught a chill,” but rather a whole broad class of externally contracted heat diseases.
The illness came on severely, with a whole string of symptoms:
- Fever, with face and eyes both flushed red — the fever burned hard, the face turned bright red, and even the eyes turned red. This is a very clear sign of intense heat.
- Qi rushing upward — a current of qi pushing up from below.
- Abdominal fullness — the belly felt distended and full.
- Both bowels blocked — the stool was dry and could not be passed, and urine had almost stopped as well.
- No sweating — not a drop of sweat on the body.
💬 Note from Doctor Luo: Look at this patient — no sweat, no stool, no urine. The whole person seems to be “sealed up” — the rising and descending, the entering and exiting of qi have all stopped. Chinese medicine holds that the body’s qi must rise and descend, enter and exit, circulating without pause. Once that stops, the trouble becomes serious. And when you feel the pulse — tight and long — tight means repletion, long also means repletion: the judgment is clear. This is a replete heat pattern — heat inside, and quite fierce.
Pattern discrimination: Yangming fu excess — heat bound together with dry stool
Doctor Xu Shuwei felt the pulse, sized up the situation, and knew what he was dealing with — Yangming fu excess (阳明腑实).
What does Yangming fu excess mean? Put simply, the heat pathogen of an external contraction invades the Yangming system (the stomach and intestines), where it binds together with dry stool in the bowels — hot and blocked at the same time, forming a situation of “heat bound with dry feces.” At this point the person runs a high fever, the belly is distended, and the bowels will not move; in severe cases there is delirium and agitation.
💬 Note from Doctor Luo: Yangming fu excess is a critical pattern within externally contracted febrile disease, characterized by “high fever + constipation + abdominal distension.” At this point simply reducing the fever is useless — you must purge the dried, bound contents of the bowels, and only then does the heat have an outlet. Zhang Zhongjing set out the specific treatment for this in the Shang Han Lun.
Doctor Xu Shuwei’s plan was blunt and direct: take Da Cheng Qi Tang.
Doctor Xu Shuwei wanted a strong purge — and the patient balked
Da Cheng Qi Tang (大承气汤, Major Purgative Decoction) is the fierce purgative formula of the Shang Han Lun. Its main force is da huang (rhubarb) and mang xiao (mirabilite), supported by hou po (magnolia bark) and zhi shi (unripe bitter orange) — a formula that sweeps everything downward, aimed precisely at serious conditions like Yangming fu excess.
💬 Note from Doctor Luo: Da Cheng Qi Tang was famous in ancient times as a “fierce medicine” — its purging power is enormous, and it was not used lightly except in critical cases. In the Song dynasty the emperor had the Shang Han Lun printed and distributed to the common people, so most people at the time had at least heard of this formula — and knew how fierce it was. When Doctor Xu Shuwei told Li Chen to take it, Li Chen balked: can my body really handle such a strong medicine?
While the patient hesitated, another doctor spoke up first: “No need for Da Cheng Qi Tang — let me give you a little Xiao Chai Hu Tang instead.” Xiao Chai Hu Tang (小柴胡汤, Minor Bupleurum Decoction) is a gentle formula that harmonizes the Shaoyang level; drinking it is not unpleasant. The result? It did nothing.
Then they switched to Da Chai Hu Tang (大柴胡汤, Major Bupleurum Decoction) — which also contains rhubarb and can move the bowels, so in principle it should have been on the right track. Yet when they tried it, it still did nothing.
💬 Note from Doctor Luo: Why no effect? Xiao Chai Hu Tang is oriented toward harmonizing, and its force was insufficient. Da Chai Hu Tang does contain rhubarb, but the dosage and combination were still not quite up to the mark. When the illness is heavy and the medicine is light, it is like a small fire under a great pot of water — the water never comes to a boil.
A bigger dose finally purges the dry stool — the illness is “cured,” and the patient feels smug
The other doctors would not give up, so they went further and augmented Da Chai Hu Tang — increasing the amounts of rhubarb, bitter orange, and the rest. This time it worked: the bowels moved, and a pile of dry, hardened fecal masses that had been jammed in the intestines came out. Once the stool passed, the heat was carried out with it, and the patient felt better.
Now Li Chen felt smug, and even bragged that he “knew a little medicine”: “See — no Da Cheng Qi Tang needed after all!” You see? I didn’t take that fierce medicine, and the illness is cured anyway, isn’t it?
Doctor Xu Shuwei listened, smiled, and said something heavy with meaning: “苟图目前，贻祸于后” — “If you only seek comfort for the moment, you are storing up disaster for later.”
💬 Note from Doctor Luo: What does “seeking comfort for the moment” mean? It means thinking only of present comfort. Doctor Xu Shuwei saw the disease thoroughly: the root of this illness is replete heat-toxin bound in the organs. Purging once and getting things moving is not the same as clearing the toxin out. By taking the easy road and refusing the heavy hand, you have left the toxin inside the body — that is not a cure, that is burying a land mine. He told the patient: your illness may be gone for now, but sores will certainly erupt on your body later.
The patient heard this and, in his heart, probably shrugged it off — the illness is cured, and you’re telling me I’ll get sick again? Aren’t you just cursing me?
Half a month later, it came true: a great boil on the back, hard as stone
Sure enough, half a month later, the prophecy came to pass.
Li Chen suddenly felt something wrong on his back — a sore had appeared, red in color. The next day a great lump swelled up on his back, as large as a plate, hard as stone. Pressing on it, it was “thump thump” — and the pain was unbearable.
Now Li Chen was terrified. Why so frightened? Because a boil on the back was a life-threatening illness in ancient times.
💬 Note from Doctor Luo: In the old days people were deathly afraid of “back boils” — the carbuncles and abscesses on the back could genuinely kill. Everyone knows Fan Zeng (范增), the “second father” of Xiang Yu, the great warlord of the Chu–Han era? In the end he died of a carbuncle on his back. So in ancient times, the moment a family heard that someone had a boil on the back, everyone was terrified — the patient was walking past the gate of death.
Li Chen hurriedly sent for Doctor Xu Shuwei: “Doctor Xu, when you said I would grow a sore, I truly did not take it seriously — and now the sore has really come! Please, take a look!”
Doctor Xu Shuwei looked at it and, to the contrary, reassured him: “This is a skin sore (chuang yang), not a deep malignant carbuncle (du ju). It is still manageable.”
💬 Note from Doctor Luo: A deep carbuncle and a surface sore are different things: the deep carbuncle may look shallow on the outside, but its root runs extremely deep and is the hardest to treat; a surface sore is comparatively superficial and much easier to handle. With one sentence, Doctor Xu Shuwei settled the patient’s heart.
And he added one more remark: “If you had listened to me that day and taken the Da Cheng Qi Tang, how could this disaster befall you today?” — because the toxin was never fully cleared back then, you have this now. And with that, he treated the sore for several days, and the illness was cured.
How did he know in advance that sores would appear? One sentence from Zhang Zhongjing reveals the secret
Someone asked Doctor Xu Shuwei: “How did you know he would develop sores later?”
Doctor Xu Shuwei quoted a passage from Zhang Zhongjing — “Zhongjing says: when the Fuyang pulse is slippery and tight…” — because when he had examined the patient, he had also felt the Fuyang pulse (趺阳脉).
💬 Note from Doctor Luo: Where is the Fuyang pulse? On top of the foot — at the raised spot on the instep, near what the ancients called the Chongyang point (ST 42). In Zhang Zhongjing’s era, physicians followed the method of “three regions, nine positions” (三部九候) — they felt pulses all over the body, not just the cunkou pulse at the wrist. The Fuyang pulse reflects the spleen and stomach. Doctor Xu Shuwei was extremely careful in pulse-taking — he felt the pulse on the foot too, and that is where he found the clue.
What did Zhang Zhongjing say? The original text: “滑者胃气实，紧者脾气强，持实击强，痛还自伤” — “A slippery pulse means the stomach qi is replete; a tight pulse means the spleen qi is strong. Grasping the replete to strike the strong, the pain turns back and wounds oneself.”
What does that mean? The Fuyang pulse was both slippery and tight — slippery means the stomach qi is replete, yang qi vigorous; tight means the spleen qi is strong, yin-cold abundant. If these two go to war — “grasping the replete to strike the strong” — it is like gripping a blade with your bare hand: you wound yourself. The stomach and spleen battle each other and injure their own body, and the result is sores (chuang yang).
💬 Note from Doctor Luo: Doctor Xu Shuwei did not feel the pulse just for show. He had Zhang Zhongjing’s original text memorized, and the moment he touched the pulse he could match it to the classic teaching. This is the true skill of a master physician: every single diagnostic judgment rests on classical evidence. When he felt that slippery-tight Fuyang pulse, he knew this patient’s spleen and stomach qi were at war and that sores would erupt later — and so it proved.
The principle: diseases have depth, medicines have weight, and toxin must be purged completely
Through this case, Doctor Xu Shuwei also taught an important principle of using medicine.
He said: diseases have depth, and the force of medicines has weight. Treating illness is like compounding a prescription — you must weigh and measure at every step. When the disease is deep and severe, the medicine must be fierce and heavy; when it is shallow and mild, the medicine must be light. Medicines whose force moves downward can be taken before meals; diseases located in the upper burner call for light medicines, which can be taken after meals.
💬 Note from Doctor Luo: Those two characters — “light and heavy” — are the real kung fu of Chinese medicine. An old physician once told a story from his student days: treating a patient with lung and stomach disease (an upper-burner condition), he wrote out a large, heavy prescription and saw no effect. His teacher arrived, and with a “snap” slashed all the dosages way down — three grams, six grams, gently applied — and it worked. The puzzled student asked why. The teacher said: “The upper burner is like a feather — unless the medicine is light, it will not rise.” For upper-burner illness, the medicine must be as light as a feather; if it is heavy, it presses the pathogen down instead. That is the art of weighing and measuring.
Doctor Xu Shuwei looked at this patient: the toxin was extremely heavy — high fever, bright red face, qi rushing upward, distended belly, both bowels completely sealed. In a situation like this, you must use herbs like rhubarb and mirabilite to withstand the poisonous qi of the organs and channels, purge it several times, and unload the heat pathogen from the organs — only then can the body slowly recover.
Doctors today are overly cautious and often fail to see the root of the illness. They use a Da Chai Hu Tang, see that the bowels have moved, and think the disease is cured — that is not acceptable. The bowels may have moved, but the toxin is still inside with no place to go, and sooner or later it will erupt through the surface of the body. So, do not rejoice the moment the stool passes — that may be exactly when you have stored the disaster inside.
Bonus: Why does the body react when you attack pathogens — or tonify deficiency?
Now comes the most vivid part of this case — Doctor Luo Dalun extends the lesson to how we care for ourselves today.
First, when attacking pathogens, patients tend to give up halfway. The ancients had three great methods for attacking pathogens: sweating, vomiting, and purging (汗、吐、下) — inducing sweat, inducing vomiting, inducing diarrhea.
💬 Note from Doctor Luo: Zhang Congzheng (张从正), one of the Four Great Masters of the Jin–Yuan period (the generation before Zhu Danxi), used the three methods of sweating, vomiting, and purging superbly — yet today, very few doctors know how. Why? The sweating method is still manageable; but the vomiting method — making you throw up — is terribly unpleasant; and the purging method — making you have diarrhea — gives you a sore belly. The patient cries “I can’t take it!” and refuses the doctor, and the pathogen stays inside, burying a land mine. Then one day, when the upright qi is weak and the pathogen has grown strong, it erupts — just like this Li Chen: wow, a great boil on the back.
Second, when tonifying deficiency, there are also “healing reactions” during which the body pushes out old problems — and these are even easier to misunderstand.
💬 Note from Doctor Luo: For example, many people drink Yu Ling Gao (玉灵膏, Jade Spirit Paste — a paste that tonifies qi and blood) and develop “heat” symptoms, then get scared and stop. Doctor Luo says the vast majority of Yu Ling Gao “heat” he has seen is not yin deficiency with liver fire — it is spleen deficiency with heavy dampness. Look at the tongue: plump tongue body, thick greasy coating, lots of saliva — the spleen and stomach are blocked and cannot transform and transport, so the nourishment you pour in turns into fire. What to do? Open the passage first: take some Da Shanzha Wan (大山楂丸, Big Hawthorn Pill) to disperse food stagnation, or Xiangsha Yangwei Wan (香砂养胃丸, Aucklandia and Amomum Stomach-Nourishing Pill) to lift the spleen-stomach function and transform the dampness — then tonify qi and blood, and no more “heat.”
There is another kind of “heat” that is actually good news — the body’s qi and blood have grown strong enough to start solving old problems. This is called “qi rushing at the disease focus” (气冲病灶).
💬 Note from Doctor Luo: People who practice qigong talk about “qi rushing at the disease focus”: when qi and blood are sufficient, the troops arrive, discover enemies in a certain spot, and the battle begins — so your tooth starts aching, your joint starts hurting. A toothache shows the tooth has a problem; a joint ache shows the qi and blood there need to open up — once they open, it heals. This is actually a signal that the body is repairing itself and the medicine is working. Of course, if your spleen and stomach are weak and cannot transform, then it is “deficiency unable to receive tonics” — also a kind of blockage; open it first, then tonify. In short: as long as the overall direction is right, don’t panic at the reactions — help the body open its passages, and keep tonifying.
Conclusion: Fortify the upright and expel the pathogen — never leave the pathogen inside
To sum up this case: Doctor Xu Shuwei saw clearly and felt sorry for the patient — if you had been willing to use the heavy hand back then and purge the toxin completely, why would you have grown a great boil on your back half a month later and walked past the gate of death?
💬 Note from Doctor Luo: The patient–doctor psychology here is the same in every age: patients always want to take “comfortable medicine,” and some doctors, afraid of offending anyone, write light prescriptions — and the illness is never properly resolved. A master like Doctor Xu Shuwei dared to use the heavy hand and dared to tell the truth — that is what it truly means to be responsible to the patient. Caring for the body comes down to eight characters: fortify the upright and expel the pathogen (扶正祛邪). Fortifying the upright means tonifying qi and blood and regulating yin and yang; expelling the pathogen means transforming phlegm-dampness, dissolving blood stasis, releasing constraint, and clearing cold. If there is some uncomfortable reaction along the way, understand that this is the body expelling disease; but as long as the overall direction is right, persist until the pathogen is sent out — never leave the pathogen behind. Whatever stays inside the body is forever a land mine.
That is the story for today. Adapted from Doctor Luo Dalun’s narration of Doctor Xu Shuwei’s case records; the case is from the Shang Han Jiu Shi Lun (Ninety Discussions on Cold Damage).