Phlegmy Cough That Won’t Go Away? Doctor Luo on Why Phlegm Comes from the Spleen and Kidneys — Not Just the Lungs
💬 Note from Doctor Luo: Dear friends, good morning, everyone. After COVID, many friends developed coughing and phlegm that lasted a very long time — some still have phlegm to this day. So now I want to explain phlegm to you properly — what phlegm really is — and touch on coughing along the way. Yesterday I talked about herbs that regulate qi, resolve phlegm and stop coughs; today we continue from there.
Opening: after COVID, why won’t the phlegm just go away?
Since the pandemic, for many people the cough and the phlegm have become an old companion — the illness itself cleared up long ago, but the phlegm refuses to leave. Doctor Luo says that to understand what phlegm really is, we first have to go back to yesterday’s cough-suppressing, phlegm-resolving herbs.
💬 Note from Doctor Luo: Yesterday I introduced a number of herbs that regulate qi, resolve phlegm and stop coughing. And I want to stress — you absolutely must distinguish cold from heat, this point is especially important. People ask, which one of these herbs should I use? There’s a pile of cold herbs and a pile of warm herbs — which do you pick? Let me tell you: once you’ve distinguished cold from heat, you can pick almost anything within that direction. Of course, an experienced practitioner will have personal preferences and adjust according to the case, but as long as you haven’t confused cold and heat, any herb you choose within the right direction will work very well. If you’re looking at a formula, or checking a patent medicine at the pharmacy, and wondering which one fits — look at which category of herbs dominates, and that tells you.
So the first foundation of treating cough and phlegm is distinguishing cold from heat — get this step right, and everything after is more or less the same, with excellent results. And these lung-opening, cough-suppressing, phlegm-resolving herbs are usually meant for the acute stage of an external-contraction illness, to transform what is called “visible phlegm.”
Don’t fixate on the lungs: every organ system can make you cough
But Doctor Luo warns there is a problem — sometimes people stare too hard at opening the lungs, resolving phlegm and stopping coughs.
💬 Note from Doctor Luo: Why? Because that acute illness — those symptoms caused by external contraction — is just one episode in your long life; it’s not something you have forever. But if you have phlegm on a daily basis, or the phlegm just won’t clear after a cold, or you often produce phlegm in ordinary times — then what’s going on? This is what I want to tell you: don’t only look at the lungs. The ancients said, “All five viscera and six bowels can cause coughing” — any organ system can make you cough, and by extension, can produce phlegm.
Take liver fire invading the lungs, for example: the liver belongs to wood, the lungs belong to metal, and normally metal controls wood. But if liver fire blazes too fiercely, wood generates fire, and that fire is so strong it “melts” the lung-metal instead — a pattern called insulting the lung metal. When this happens, you cough.
💬 Note from Doctor Luo: This kind of cough comes from liver fire invading the lungs, and the treatment is to drain the liver fire — once the fire is released, the cough resolves. In fact, the serious respiratory and lung diseases I’ve seen are very often connected to liver fire — especially in women, especially severe lung disease like lung cancer and interstitial pneumonia, these grave, life-threatening lung conditions often relate to liver fire. Getting angry builds liver fire, and that is an extremely important trigger. This kind of cough often shows up as a dry cough, coughing with blood-streaked sputum, no phlegm, or sometimes a little yellow phlegm.
The root of phlegm: the spleen generates it, the kidneys are its foundation
In acute illness we rightly think about the lungs a lot; but once the acute phase has passed, if the cough drags on for a long time, or you cough in everyday life — that’s when you need to focus on the spleen and stomach.
💬 Note from Doctor Luo: The ancients said, “The lungs are the vessel that stores phlegm” — the lungs are just a container for phlegm, like a bucket. If phlegm won’t move out and keeps piling up, where does it actually come from? The lungs only store it. So what is the source that generates phlegm? The spleen is the source that generates phlegm — the source is in the spleen; and the kidneys are the root of phlegm — the most fundamental cause lies in the kidneys.
A weak spleen and stomach cause phlegm to form inside the body — this kind is invisible phlegm; if it rises into the lungs and becomes something you can actually cough up, it’s visible phlegm. Why does a weak spleen and stomach generate phlegm? Doctor Luo explains two reasons, plus one linked relationship — three aspects in total:
First, the spleen and stomach belong to earth — in the five-element system, earth controls water; water is held back by earth. Earth is the governor of water. The spleen’s job is to transform and transport dampness, to “keep the body’s water in order.” When the spleen and stomach are weak, when spleen-earth is weak, water-dampness floods — the water that should leave the body through sweat and urine can’t get out, gets stuck inside, and as it accumulates it gradually turns thick and sticky, becoming phlegm.
Second, the spleen and stomach transform food. When transformation is weak, some garbage stays in the body — for example, rich, fatty, sweet foods. Eat fatty pork, braised pork, big fish and big meat every day and the spleen and stomach get injured, unable to transform all that fat; it can’t be metabolized out, the belly grows bigger and bigger, the body gets fatter and fatter, and that garbage starts generating phlegm, merging with the water-dampness phlegm from before.
Third, spleen-earth is the “mother” of lung-metal. The spleen and stomach belong to earth, the lungs belong to metal, and earth generates metal — when the spleen and stomach weaken, the child, lung-metal, also weakens, so external pathogens easily get in, and in the struggle they brew up all sorts of new phlegm.
💬 Note from Doctor Luo: You see, these three aspects decide it: because the spleen and stomach are weak — from water-dampness, from rich fatty food, to the weakened lungs letting external pathogens in and your body fighting them to make phlegm — that’s why phlegm multiplies. Nowadays we often fail to recognize this. The moment someone coughs and has phlegm, we assume it’s the lungs, an airway inflammation — when in fact sometimes adjusting the lungs alone simply doesn’t work.
One move that works: Doctor Zhang Xichun’s Chinese yam water
Many people cough for weeks after a cold and never get better — what to do? Doctor Luo keeps returning to one tried-and-true experience — simmering dried Chinese yam slices in water.
💬 Note from Doctor Luo: Take a big handful of dried yam slices and simmer them into a drink, or take two yams and blend them with yam powder into a thick porridge and swallow it down — many friends get better after just a few servings. People find it very strange: how can eating Chinese yam cure a cough? Why does an obstinate cough resolve after eating yam twice? It’s because it strengthens the spleen and stomach — the spleen is the source that generates phlegm, so if you fix the source, if the spleen and stomach grow strong, the lungs grow strong too, resistance rises, upright qi is sufficient, the external pathogen gets expelled, and the phlegm inside the lungs diminishes; and with the spleen and stomach’s upright qi sufficient, water-dampness is transformed and transported normally, so the invisible phlegm generated inside the body also decreases. Restoring spleen and stomach function is therefore extremely important.
This approach wasn’t invented by Doctor Luo — he learned it from Doctor Zhang Xichun, who always had his patients drink Chinese yam water during recovery. That was his signature move.
A true story: Brother Liu, pulled back from the brink of death
Doctor Luo tells a case that made a deep impression on him — the older brother of a classmate, Brother Liu, who at the time had severe asthma.
💬 Note from Doctor Luo: His asthma was so severe the hospital had almost given up on him; the hormones he was on had already been pushed very hard. When an attack hit, he was in real danger. When he came to see me in Beijing, two people had to support him on either side — he said the doctors had concluded this man was not going to make it. I looked at him and asked: do you currently have an external contraction? He did, so I wrote a formula for the external contraction to clear the triggering factor. In addition I told him: every day, simmer 100 grams of dried yam slices in water — whenever you’re thirsty and want a drink, drink nothing but that yam water. I learned this trick from Doctor Zhang Xichun, and after learning it I’ve used it for patients like him. As a result, this man improved visibly — he recovered.
Later, Doctor Luo ran into him several times on the street, and mutual friends would say: “You pulled him back from the brink of death.”
💬 Note from Doctor Luo: Why did it work? At the time he was coughing and wheezing terribly, barely able to catch his breath. What were we doing? We were vigorously tonifying the spleen and stomach — building up spleen qi so that lung qi could rise. Chinese medicine believes in treating the root — during acute illness you treat the acute illness; the cold formula I gave him was taken for only three to five doses, a matter of days. But the spleen-strengthening care that followed had to be done over a long stretch of time. That is the core principle of how Chinese medicine treats disease.
Acute cases treat the branch; chronic cases treat the root
Doctor Luo sums up the approach to cough very clearly: in acute, severe illness, treat the branch first; once things ease, start looking for the root — and for cough and phlegm, the root is the spleen and stomach.
💬 Note from Doctor Luo: The lung-opening, cough-suppressing herbs you use in acute illness — for heat patterns, loquat leaf and chuan bei mu (Fritillaria bulb); for cold patterns, pair in kuan dong hua (coltsfoot flower) and zi wan (aster root), add a little jing jie (schizonepeta), jie geng (platycodon root), a bit of chen pi (aged tangerine peel) — all of these are for temporary use; you can’t take them for two months straight. Where is the fundamental adjustment? In the spleen and stomach. You can even simply take Xiang Sha Liu Jun Zi Wan (Six Gentlemen Pill with Costus Root and Amomum) — the Six Gentlemen Decoction plus xiang sha — to strengthen spleen and stomach function. Keep tonifying the spleen, and drinking yam water helps too. Keep tonifying the spleen, and before long upright qi is sufficient — you discover there’s less phlegm, your head gradually clears, you stop coughing. What is this? It’s building up the spleen and stomach — spleen-earth is the mother; when the mother is well, the child, lung-metal, is well. This is called treating the source.
The deeper root: the kidneys — the fire of the Life Gate generates spleen-earth
The spleen and stomach are this important — so why do the spleen and stomach themselves break down? Doctor Luo digs one level deeper:
💬 Note from Doctor Luo: When the spleen and stomach malfunction, a large share of the time it’s caused by insufficient kidney qi — especially when spleen yang is deficient, most of the time it traces back to kidney qi deficiency. The body operates on this kind of deficiency logic: a deficient spleen and stomach can also drag down the kidneys, and deficient kidneys can drag down the spleen and stomach. Trace it to the very root — the spleen is the source that generates phlegm, so what is the deepest, the invisible underground root that grows it? Coughing caused by insufficient kidney qi is a deeper-layer cough, and its phlegm is often more severe.
The kidneys govern qi transformation — when kidney qi is insufficient, transformation fails, water-dampness accumulates and can’t be discharged from the body. It’s like the fire under a boiler slowly going out: the water circulation in the boiler above starts to malfunction.
💬 Note from Doctor Luo: What is the root within the kidneys? Kidney fire — we call it the fire of the Life Gate (ming men). The kidneys contain fire and water; water and fire together, water embracing fire — that’s the model of the kidneys. What does the fire of the Life Gate generate? Fire generates earth — it generates spleen-earth. So when kidney yang is deficient, when it wanes, spleen-earth and spleen-yang become deficient; and when spleen-yang is deficient, water-dampness floods. Can you see the whole chain now?
So what to do? When kidney-yang deficiency appears, pay attention to tonifying the kidneys — there are many kidney-tonifying formulas, and Jin Gui Shen Qi Wan (Kidney Qi Pill from the Golden Cabinet) is a proper, orthodox kidney-yang tonic.
💬 Note from Doctor Luo: Even in the past, why did we treat cough and wheeze with gecko and the like? They all tonify the kidneys — tonify the kidneys to help them grasp the qi. For managing chronic cough: for the residue left after an external contraction, tonifying the spleen is usually enough; but for the kind that persists year-round, that never quite stops coughing, you must consider the kidneys. I adjust lungs, spleen and kidneys all together — resolve phlegm at the lungs, strengthen the spleen at the spleen, and at the kidneys warm yang and help them grasp the qi. For people with long-term phlegm or even long-term cough, consider the lungs, the spleen and the kidneys — they’re one connected line.
Cough in the elderly: always think of the kidneys
The same line of thinking shifts focus for different groups. Doctor Luo puts special emphasis on elderly people:
💬 Note from Doctor Luo: In acute cases, when I’m adjusting the formula, sometimes I also add spleen tonics — a bit of bai zhu (atractylodes), fu ling (poria), a bit of dang shen (codonopsis). If yang qi is insufficient, I add these spleen-qi tonics; if the person is yin-deficient, I can add something to nourish yin, but tonifying the spleen is never dispensable. And if the illness has truly gone on a very long time and the person is very weak — this is no joke, you really do need to consider kidney qi. In my experience, for the average middle-aged person, unless the kidneys show some special disorder, you don’t necessarily need to think about the kidneys. Take that Brother I mentioned — he had a special problem: he was very frank with me, said that in his youth he was dashing and handsome, almost like a movie star, had a lot of girlfriends, indulged without restraint — so as he aged a little, his kidney qi became deficient, and he developed severe asthma, full of regret. Afterwards he really changed as a person, took up Buddhist practice, became deeply devout — he suddenly realized all those things were illusions, and the body is what truly matters. Ordinary middle-aged people aren’t that deficient; a modest tonic suffices — you don’t need heavy supplementation. For elderly friends, this really must be considered — many elderly people cough for years; how can we not consider the kidneys? Kidney qi is insufficient because age itself consumes it, so we need to give it more thought.
Closing: fortifying upright qi is always the long-term priority
Doctor Luo also mentions the heart in passing — when heart fire or heart qi is weak, coughing can also occur, and this kind of cough with much phlegm is something Doctor Zhang Xichun discussed extensively: when the Great Qi sinks (da qi xia xian) — the chest qi that anchors the body collapses downward — coughing appears too, and the voice changes, turns hoarse.
💬 Note from Doctor Luo: These are all situations where heart-lung function has a problem. What we now call sinking of the Great Qi is really a malfunction of heart-lung function. What I want to share with you today is this: yesterday we covered the lung-opening, qi-regulating, phlegm-resolving formulas that are available for acute illness — but don’t cling to them. In an acute phase they work beautifully, yet I believe once one or two weeks have passed, you should start thinking about the spleen and kidneys. I can still think about opening the lungs, but I should also consider tonifying the spleen, start preparing to strengthen it — because fortifying upright qi is the foundation. Why can’t your body shed so much dampness? Why does the dampness condense? Why does your lung fail the moment an external pathogen arrives? It’s all insufficient upright qi. So at this stage tonifying the upright is the root — if you can build upright qi to sufficiency, transform the dampness away, dissolve the phlegm, the qi flows smoothly and there’s no problem.
Fortifying upright qi is always the long-term priority; expelling pathogens is usually the short-term goal. Chinese medicine says, “In acute cases treat the branch; in chronic cases treat the root” — treating the root is a long-term task and deserves the main effort; treating the branch is what you do when daily care has slipped and a pathogen has broken in — a necessity.
💬 Note from Doctor Luo: You can’t keep clearing external pathogens forever — with insufficient upright qi, who can fight a war every single day? So treating the branch is the short-term goal; it’s for when you’re truly in trouble and have no other choice. I want to make this reasoning clear to everyone. Dear friends, that’s the big picture on phlegm for today. Thank you for listening — I hope it helps with your post-COVID recovery care and with everyday maintenance. Tomorrow at this same time, we’ll continue with the principles of Chinese medicine. See you tomorrow!
Compiled from Doctor Luo Dalun’s health lectures (cough and phlegm series: the spleen generates phlegm, the kidneys are its root).