Boils on the Back, Red and Swollen? Fix the Interior First, Then Clear the Exterior Pathogen
What people search for: boil on the back / sore on the back / red swollen back / pain below the shoulder blade / vomiting after eating / dark complexion
In medical terms: yongju (boils and carbuncles) · fabei (carbuncle on the back) · middle jiao distention and fullness · phlegm-damp obstructing the interior · vital qi deficiency with pathogen depression
Opening: the disease looks like a skin problem — but the root is in the belly
Today Doctor Luo Dalun continues the story of Doctor Zhu Danxi at work, and the topic is still yongju (痈疽) — in plain words, boils that grow on the skin. Yesterday’s case was an elderly woman with a deep carbuncle at the back of her head; Doctor Zhu Danxi used wine-prepared Dahuang (rhubarb) together with wine-mixed Renshen (ginseng), and after one night’s sleep the boil had drawn in. Today’s patient has the problem on his back, and treating him is far more complicated — because the moment Doctor Zhu Danxi examined him, he saw it: this disease looks like a problem of skin and flesh, but its root is in the belly. To cure a boil on the back, you first have to solve the problems inside.
💬 Note from Doctor Luo: That sentence is the key to today’s case — Doctor Zhu Danxi never treated a boil by staring at the boil. He always looked at the whole person first: is anything blocked inside? Is the body deficient? Is there phlegm? When the interior is put in order, the exterior pathogen has a way out. As you study this case, what you are really learning is his method for treating miscellaneous diseases.
Who was the patient? A sturdy fifty-year-old man with a dark complexion
The patient was a fifty-year-old man. In ancient times fifty was already fairly old. Doctor Zhu Danxi described him in four characters: xing shi se hei (形实色黑) — sturdy build, dark complexion.
💬 Note from Doctor Luo: “Sturdy build” — his body was quite strong, not one of those thoroughly depleted cases; he looked solid and well-fed. But the “dark complexion” is a warning sign. In Chinese medicine, “black is the color of the Kidney” — people whose kidney qi is insufficient often take on a dusky, darkened tone over the whole body. So put a question mark next to that “dark complexion” — there is a story hidden in it.
Here was a husky fellow with a dark face. Doctor Zhu Danxi already had a suspicion forming: this man probably had insufficient kidney qi. But how could a man with deficient kidney qi grow a boil on his back? Don’t rush — read on.
The symptoms: a red swollen boil on the back, plus pain below the shoulder blade
The man’s illness was bei sheng hong zhong (背生红肿) — a red, swollen area had grown on his back, a yongju. When a carbuncle grows specifically on the back, the ancients had a special name for it: fabei (发背), and it was considered a very dangerous disease.
Along with the boil on his back, there was one strange additional symptom: pain below the shoulder blade (肩胛骨下边痛).
💬 Note from Doctor Luo: A boil on the back is understandable — but why pain below the shoulder blade? Set that strange symptom aside for a moment; we will come back to it. In the prescription Doctor Zhu Danxi wrote later, the answer to all of this is right there.
Now the pulse. Doctor Zhu Danxi took the pulse and found it: floating, rapid, surging and tight (脉浮数而洪紧). Floating — the pulse is felt at the surface, which says the pathogen is at the body surface, just as in an exterior wind-cold invasion; and it is rapid, tight and large, which says the struggle between vital qi and pathogen is extremely fierce.
One more symptom: shi yi ou (食已呕) — he vomited right after eating.
💬 Note from Doctor Luo: Look at all these symptoms together — don’t they seem messy? A boil on the back, pain below the shoulder blade, a floating rapid surging tight pulse, vomiting after meals — these do not look like they belong to one disease at all. But as soon as Doctor Zhu Danxi wrote his prescription, the whole picture became clear.
It happened in midwinter: Doctor Zhu Danxi prescribed a “cold formula”
At the time it was winter (冬月) — the dead of winter. What formula did Doctor Zhu Danxi open with? Mahuang-Guizhi decoction (麻黄桂枝汤).
💬 Note from Doctor Luo: That “Mahuang-Guizhi decoction”, as I puzzle it out, should be Gui Zhi Ma Huang Ge Ban Tang (桂枝麻黄各半汤) — take the Guizhi decoction (Cinnamon Twig Decoction) and the Mahuang decoction (Ephedra Decoction), cut each to half its normal dose, and combine them. One side expels the pathogen, the other supports the vital qi; both are smaller than the originals.
Why this formula? Doctor Zhu Danxi reasoned like this: this man’s pathogen was still in the Taiyang channel (太阳经), still at the body surface — and because time had passed, the pathogen had already begun to weaken. If the pathogen were at full strength and the body were fighting it head-on, you would use the full Mahuang decoction to strike it from the front. But now the pathogen was already weak, so the Mahuang part was cut to half — just a little is enough. At the same time the vital qi was not sufficient either: the body wanted to resist but lacked the strength, so he used the Guizhi decoction part to support the vital qi and harmonize the nutritive and defensive (ying and wei) qi.
💬 Note from Doctor Luo: One side expels the pathogen, the other supports the vital qi — and both doses are smaller than usual. Here is why: at this stage the pathogen is weak, lingering at the body surface; the vital qi wants to push out a sweat to drive it away but cannot manage it, so the pathogen stays congested at the surface. If you support the vital qi and expel the pathogen at the same time — a small dose of Mahuang decoction to scatter the pathogen, the Guizhi decoction to harmonize ying and wei — the pathogen can be completely cleared.
Why use a cold formula to treat a boil? The back is yang, and the Bladder channel runs right across it
Someone will ask: this formula is usually for exterior illnesses — why did Doctor Zhu Danxi use it for a carbuncle on the back?
💬 Note from Doctor Luo: Because at this moment the pathogen was also at the body surface. The back belongs to yang, and the foot taiyang Bladder channel (足太阳膀胱经) happens to run along the back. When the pathogen lingers at the surface, the surface cannot sweat, the pathogen cannot get out — so you open the surface and drive the pathogen outward. Using a cold formula for this purpose is exactly the same logic. This is what the ancient doctors called the “correct method” (正治法) of treating yongju: open the surface, scatter the pathogen, and the boil naturally dissolves.
The art of the additions: wine-prepared Huangbai, raw Fuzi, Renshen — every single herb has a reason
On top of the Mahuang-Guizhi base, Doctor Zhu Danxi added a whole string of herbs, and every one of them has its own story.
Wine-prepared Huangbai (酒黄柏) — Phellodendron bark processed with wine. Huangbai clears heat; after wine-processing its action rises, so it clears upper jiao heat. Because the boil sits high on the back, the pathogen is in the upper part of the body, and the wine-prepared Huangbai carries the medicinal force upward to meet it.
Raw Fuzi (生附子) — why add aconite? To support the vital qi and support the kidney qi. Because this man’s complexion was dark, Doctor Zhu Danxi suspected his kidney qi was insufficient, so he used Fuzi to support kidney qi.
Renshen (人参, ginseng) — ginseng tonifies qi; Doctor Zhu Danxi held that it also tonifies blood, so it tonifies both qi and blood. Ginseng paired with Fuzi — one above, one below — lifts the whole vital qi; combined with the Guizhi decoction harmonizing ying and wei, the strength of the support is complete.
💬 Note from Doctor Luo: Notice that ginseng and aconite are used together here — some modern pharmacies would not dare to fill this prescription, because the “Eighteen Incompatibilities” (shiba fan, 十八反) tradition says aconite is incompatible with ginseng. But in fact the Eighteen Incompatibilities are not especially authoritative; many physicians have held that incompatible herbs used together can work even better. Doctor Zhu Danxi put them in the same formula without hesitation.
Gualouzi (瓜蒌子, Trichosanthes seeds) — the gualou plant comes as whole gualou, gualou peel and gualou seeds. The seeds both drain downward and transform phlegm. Doctor Zhu Danxi judged that this man had phlegm inside — look at his sturdy build; he must have eaten well, rich fatty and sweet food, and that easily breeds phlegm — so he used gualouzi to transform it.
Gancaojie (甘草节, licorice nodes) — these are the brownish, dark, gummy nodules found in the core of the licorice root. Licorice harmonizes the other herbs and has some toxin-resolving power, but the licorice node specializes in resolving toxin — above all the toxin of sores and carbuncles — and that is why it is used for skin lesions.
💬 Note from Doctor Luo: This single herb, gancaojie, shows how meticulous Doctor Zhu Danxi was in choosing medicines — he knew exactly which herb to use in which situation; that is something acquired through years of reading and practice. Nowadays we treat fewer boils and carbuncles, so most people do not know this herb; in ancient times gancaojie was an everyday remedy.
Qianghuo (羌活, Notopterygium) — Qianghuo disperses wind and unblocks the collaterals. This man must have a swelling inside, because congealed qi and blood are what form a boil; his qi and blood must not be circulating. Qianghuo keeps qi and blood moving and scatters wind and pathogen, helping the Mahuang decoction push the pathogen outward.
Qingpi (青皮, green tangerine peel) — Qingpi breaks up stagnant qi. There must be qi congestion — that is what makes qi and blood gather together into a boil — so Qingpi opens up the congested qi mechanism.
Huangqin (黄芩, Scutellaria) — clears upper jiao heat.
Banxia (半夏, Pinellia) — transforms phlegm and descends qi.
Shengjiang (生姜, fresh ginger) — on one hand it keeps the formula from being too cold; on the other, “phlegm will not transform without warmth” — ginger transforms phlegm, disperses spleen stagnation and regulates qi.
💬 Note from Doctor Luo: Look at this combination — Renshen, Banxia, Huangqin, Shengjiang, licorice, with Huangbai standing in for Huanglian (Coptis). Do you see what is hiding in it? The line of thinking of Banxia Xiexin Tang (Pinellia Heart-Draining Decoction, 半夏泻心汤) or Shengjiang Xiexin Tang (Ginger Heart-Draining Decoction, 生姜泻心汤)! The xiexin family of formulas comes from Zhang Zhongjing’s Shang Han Lun (Treatise on Cold Damage) and treats distention and fullness of the middle jiao.
The mystery solved: why did he vomit after eating? Why did his shoulder blade hurt?
What are the xiexin-type formulas for? When the spleen and stomach are weak, the ascent and descent of the qi mechanism fall into disorder, and a mixed cold-and-heat (寒热错杂) state parks itself in the middle jiao — the middle jiao becomes distended and full (痞满), the qi mechanism cannot rise and fall properly, and everything gets stuck. What happens with fullness? Vomiting — stomach qi is supposed to descend, but it is blocked and cannot go down, so it can only come back up as vomiting.
💬 Note from Doctor Luo: The moment Doctor Zhu Danxi saw that the patient vomited right after eating, he understood at once: this is middle jiao fullness! Stomach qi flows downward as its normal course; if it is stuck and coming back up, the qi mechanism’s rise and fall must be disordered. When fullness blocks the rise and fall of qi and gets stuck inside, it easily produces local heat — the boil on the back is connected to this.
And the pain below the shoulder blade? Beneath the shoulder blade, on the Bladder channel, there is an acupoint called Géguān (膈关, BL46). If the chest and diaphragm are full and blocked, this acupoint reacts — it hurts.
💬 Note from Doctor Luo: Pain below the shoulder blade tells you that the qi between the chest and diaphragm is not moving freely; congested qi is affecting the smooth flow of qi and blood to the back. So Doctor Zhu Danxi saw the whole picture in an instant: you are blocked inside — phlegm-damp, food stagnation, mixed cold and heat, disturbed ascent and descent. I will add some xiexin-style medicine plus phlegm-transforming herbs to open the qi mechanism and clear the phlegm, then support the vital qi; then the Mahuang-Guizhi decoction scatters the surface, the pathogen leaves, and the body recovers.
Six doses and it dissolved: fix the interior first, then clear the exterior pathogen
With this formula, the result was liu tie er xiao (六帖而消) — after six doses, the carbuncle on the back melted away.
💬 Note from Doctor Luo: Doctor Zhu Danxi himself called this “the method of inner support for this kind of case” (此症内托之法). Look at what he did: on one hand he supported from within — tonifying vital qi, opening the fullness, transforming phlegm — and on the other he used Guizhi and Mahuang to open the body surface. There are many layers to this method; this is the work of a master. Carbuncles can be genuinely dangerous when treated badly, and Doctor Zhu Danxi cured this one in six doses.
Doctor Zhu Danxi’s critique: Neituo San must not be used blindly
After curing the disease, Doctor Zhu Danxi added a lecture criticizing the fashionable treatment of his day. He said: this disease is not what the Neituo San (Inner Support Powder, 内托散) of the Waike Jingyao (Essentials of External Medicine) — the Ruxiang (frankincense) and mung-bean formula — is for. That formula was designed specifically for people who developed carbuncles from taking mineral elixirs (dan shi, 丹石); to use it without regard for the actual pattern is, he feared, not right.
💬 Note from Doctor Luo: Here is the background story. In the Song dynasty, Chen Ziming wrote the Waike Jingyao and for carbuncles produced a formula called Neituo San containing Ruxiang (frankincense) and lüdou (mung beans) — mung beans ground to powder for people to take. Why was that formula made? At that time enormous numbers of people were taking mineral elixir drugs — mineral preparations that supposedly strengthened yang and tonified the body; everyone felt their health improving, so from the Wei-Jin period onward this fashion spread. In reality these minerals carry fierce heat. Many people were poisoned, some died, and many grew carbuncles on the surface of the body. It was precisely to treat carbuncles caused by taking elixirs that Chen Ziming wrote Neituo San — the mung beans especially resolve heat toxin. Later, when fewer people took mineral elixirs, the formula gradually fell out of use — but everyone still assumed all carbuncles should be treated with it. Doctor Zhu Danxi’s criticism: no! That formula was made for elixir-induced carbuncles; our patients today are not in that situation, so you cannot use it that way. You must always discriminate patterns and treat accordingly (bianzheng lunzhi, 辨证论治).
Compared with yesterday’s case: the same disease, completely different treatment
Doctor Luo Dalun deliberately placed these two cases side by side. Yesterday’s elderly woman was treated by Doctor Zhu Danxi with wine-prepared Dahuang with ginseng; today’s patient needed a far more complicated prescription.
💬 Note from Doctor Luo: Why the difference? The old woman’s case was one of excess — heavy heat toxin — so Dahuang was used to scour it out. Today’s man, for all his sturdy build, was actually deficient inside: dark complexion, insufficient kidney qi, and he ate well so he carried plenty of phlegm-damp. So Doctor Zhu Danxi supported vital qi, transformed phlegm, opened the knot in the spleen and stomach, and then helped the surface stagnation disperse — the treatment had many more layers. Same disease, yongju — one cleared excess, the other tonified deficiency, transformed phlegm and opened the surface. That is what it means to discriminate patterns and treat accordingly.
What we can learn: Doctor Zhu Danxi’s method for miscellaneous diseases
Two things come out of this case.
First, get to know the xiexin family of formulas. These are extremely important formulas from Zhang Zhongjing’s Shang Han Lun for middle jiao distention and fullness — we still use them constantly for spleen-stomach disorders today: they open the congested knot in the middle jiao and restore the rise and fall of the qi mechanism.
Second, learn the method of transforming phlegm. As Doctor Luo Dalun put it, in treating miscellaneous diseases Doctor Zhu Danxi gradually reveals his two great techniques: resolving stagnation (jie yu, 解郁) and transforming phlegm (hua tan, 化痰) — he was exceptionally good at dispersing congestion and dissolving phlegm.
💬 Note from Doctor Luo: In treating miscellaneous diseases, Doctor Zhu Danxi considered more layers than most physicians. In this case: he saw the patient’s sturdy build and knew he ate well and had phlegm, so he used gualouzi to transform it; he saw vomiting after eating and knew there was middle jiao fullness, so he used the xiexin line of thinking to open the fullness; he saw the dark complexion and knew the kidney qi was insufficient, so he used Fuzi and Renshen to support vital qi — and on top of all that he used the Mahuang-Guizhi decoction to scatter the exterior pathogen. Solve the problems inside first — only then can you clear the pathogen outside. That is Doctor Zhu Danxi’s method for miscellaneous diseases, and it is the very reason his book is called Dan Xi Xin Fa (Teachings of Master Danxi, 《丹溪心法》). This way of thinking is of great benefit when we look after our own health.
Compiled from Doctor Luo Dalun’s lectures on Doctor Zhu Danxi’s case records; the case is from Dan Xi Xin Fa (Teachings of Master Danxi).