Dry Throat, Lingering Cough and Sticky Phlegm After COVID? Doctor Luo Dalun on the Dryness Pathogen (Zao Xie): Know the Difference Between Cool-Dryness and Warm-Dryness (Xing Su San · Qing Zao Jiu Fei Tang)

What people search for: dry throat after COVID / lingering cough with sticky phlegm / post-COVID recovery / dry throat always wanting to cough / white sticky phlegm / nasal congestion after COVID / dryness pathogen Chinese medicine / cool-dryness vs warm-dryness / Xing Su San / Qing Zao Jiu Fei Tang / Yu Ling Gao / long COVID Chinese medicine

Medical terms for this condition: zao xie (dryness pathogen) · liang zao (cool-dryness) · wen zao (warm-dryness) · nei zao (internal dryness) · jin ye (body fluids) deficiency · xue han tong yuan (blood and sweat share the same source) · fei wei jiao zang (the lungs are the delicate organ) · fei yu da chang xiang biao li (the lungs and large intestine are internally-externally paired) · sour-sweet yin-generating method (suan gan hua yin)

💬 Note from Doctor Luo: Dear friends, good morning everyone. Some time ago I asked on Weibo: after testing positive for COVID, after recovering, what discomforts are still lingering in your body? Countless friends left messages — several thousand of them. The symptom mentioned most often was: the throat always feels dry, it always feels like you need to cough, and when you cough up something there is always a little phlegm — a little white, very sticky phlegm. Very many people have this, and they say it is quite annoying. Some also have nasal congestion — the nose feels blocked, also very annoying. What on earth is going on? Today I want to talk with you about what we call the dryness pathogen (zao xie).

One: thousands of messages, all pointing to the same problem: dry throat, sticky phlegm, stuffy nose

After “testing positive,” what is the most common lingering feeling? Doctor Luo ran a poll on Weibo; thousands of messages came in, and the answers were highly concentrated: the throat always feels dry, like you need to cough, and you cough up a little white, sticky phlegm; some people also have nasal congestion — the nose always feels blocked.

💬 Note from Doctor Luo: This is quite annoying. How does Chinese medicine explain it? We have to start from the “dryness pathogen.” Chinese medicine speaks of external pathogens as “wind, cold, summer-heat, dampness, dryness, fire” — dryness is one of those evil qi. Once we talk about the concept of the dryness pathogen today, everyone will understand why the throat is dry.

Two: the ancients noticed “dryness” long ago — a pathogen summarized from changes in the weather

Our ancestors paid close attention to nature long ago — changes in climate and changes in the external environment cause changes in the body. Winter is bitingly cold, summer is blazing hot — those are temperature changes. There is also strong wind; wind can injure people too — a gust of wind blows and you get sick. And there is dampness: when the weather is very damp, foggy and misty, even breathing is hard.

💬 Note from Doctor Luo: And there is one more — dryness: the aridity of the air. Very high humidity is uncomfortable, but the other situation is also uncomfortable: when the air is extremely dry, it also causes problems. Under normal climatic changes our bodies adapt: hot summer, cold winter, dry autumn, damp long-summer — all acceptable. But if it goes too far, that is not allowed — too much dampness won’t do, and dryness that is too severe won’t do either. Look at the great deserts: when the sun beats down, people nearly faint.

Three: who is most vulnerable? Your constitution decides which weather you fear

Changes in the external environment first affect the people whose constitution is most susceptible, and if it gets worse, even normal people can be affected. Different constitutions fear different weather:

💬 Note from Doctor Luo: People with yang deficiency — those who drink iced drinks every day, sit in air conditioning, and take cold, cooling medicines until their yang qi is very weak — tend to have problems when the weather turns cold. People with yin deficiency and heat inside, insufficient fluids, deficient yin blood, tend to have problems in hot weather. People with heavy dampness inside — indulging in rich food and drink every day, heavy phlegm-dampness, drinking a lot of water but not excreting it, with insufficient upright qi — tend to have problems in that foggy, misty weather. And there is one more type: people whose body fluids are insufficient, who have lost a lot of fluid — fluids, liquids, blood, even essence (jing) are all insufficient — what are they vulnerable to? Heat pathogen, and the dryness pathogen. Dryness and heat easily mix together, but they are not completely the same; there is also cool-dryness. So mere environmental dryness can affect people whose internal fluids are insufficient — that is how they fall ill.

Four: external dryness is not the whole story — there is also “internal dryness”: how the fluids get drained away drop by drop

Chinese medicine divides dryness into external dryness (wai zao) and internal dryness (nei zao). Dryness in the external environment is external dryness; internal dryness is when the body, for various internal reasons, has lost so much fluid, essence and blood that a very dry state forms inside the body.

💬 Note from Doctor Luo: What causes internal dryness? For example, you habitually like hot-natured foods — spicy, hot things — which drain the fluids. For example, you rack your brains thinking about problems every day — that drains yin blood; when blood is drained, fluids naturally decrease along with it. Another is staying up late — every night not sleeping, thinking, writing proposals; the body consumes a great deal. And high fever after illness — a fever is the most typical case: during a high fever the fluids seem to be dried up, and after the great battle the body often shows fluid deficiency. There is also vomiting and diarrhea: in ancient times the emetic method was used; vomiting usually does not cause much dryness, but diarrhea does — for example, eating something bad when you are out, running to the toilet every little while; when the diarrhea is severe the face caves in and you feel shriveled. Think of cholera-like illnesses in the past — violent diarrhea, watery stools like rice water; how bad could it get? The eye sockets sink in — the body’s fluids are gone; some women’s breasts even deflate. That is severe fluid loss — the body forms internal dryness.

Doctor Luo highlights a key concept — blood and sweat share the same source (blood and fluids come from the same origin): when blood is deficient and fluids are low, where does the body borrow from? From the fluids — the tissue fluids. When it borrows, the tissue fluids decrease, and the fluids (jin ye) decrease.

💬 Note from Doctor Luo: Blood and fluids are of the same origin — both are fluids of the body, and they borrow from each other. So people who are usually deficient in qi and blood — insufficient production, insufficient transport of nutrients — are already in a deficient state to begin with: qi, blood, yin and yang may all be somewhat insufficient, especially blood and yin. Yin is a broad category — blood, fluids, essence; these quiet, still substances are all called yin, and they are all somewhat insufficient. Then along comes the epidemic: the body fights the pathogen and consumes a great deal; there is fever, some people also have diarrhea, and the blood and fluids become even more insufficient. The fever subsides but they do not take good care of themselves, so the body never fully recovers.

Six: where does the dryness pathogen love to strike? The lungs are the delicate organ — entering straight through the mouth and nose

Once an internal dryness environment exists, if external dryness then acts on top of it, people easily fall ill. What does dryness pathogen injury look like? The skin surface is no longer moist, the hair becomes withered and dry; the mouth is dry, the nose is dry — some people are so dry that opening the mouth hurts; the eyes are terribly dry; the stools are dry and constipation-like, urine is scanty.

💬 Note from Doctor Luo: The dryness pathogen most easily injures the lungs — the lungs are the delicate organ (fei wei jiao zang). Dryness enters through the mouth and nose, attacks the lung organ, and easily produces all kinds of coughs, dry coughs, with a little phlegm or none at all. And the lungs and the large intestine are internally-externally paired (fei yu da chang xiang biao li) — dry, bound stools are connected with it too. In severe cases it can even lead to externally contracted illness: fear of wind and cold, headache, and so on. After COVID: dry throat, itchy throat, sticky phlegm, dry tongue, dry mouth with thirst that wants cool water to moisten it, dry skin, scanty urine, dry bound stools — these are all signs of dryness.

Seven: first distinguish cool-dryness from warm-dryness — cool-dryness: the “contracting” dryness of early autumn

In which season is the dryness pathogen dominant? Autumn — crisp autumn air, and the sun dries everything out. But dryness divides into two kinds: cool-dryness (liang zao) and warm-dryness (wen zao) — and the treatment methods are completely opposite.

💬 Note from Doctor Luo: Just at the start of autumn, the weather suddenly turns cool — you had adapted to summer’s heat, and suddenly it cools; the qi mechanism begins to collect and store inward. The nature of dryness is contractive: the qi draws inward, and the body suddenly begins to tighten up. At this time, people with insufficient fluids suddenly feel deficient on the body surface — that is cool-dryness appearing. What does cool-dryness look like? Fear of wind and cold, cough with white phlegm, a bit of coughing, headache, aversion to cold, very blocked nose, no sweating (because of the dryness the skin is very dry), and the inside of the lips is also very dry. The tongue is pale, the whole tongue surface dry. Now, cool-dryness does NOT mean that because it is dryness you must moisten it — in cool-dryness you have fluids inside, but the cool qi has contracted them excessively, so the body surface suddenly dries out. Therefore at this time you must use warm-natured medicines to disperse — get the qi and blood circulating, let the cold pathogen on the body surface scatter, and let the fluids inside come out.

Eight: Xing Su San (Apricot Kernel and Perilla Powder): warming medicines disperse and send the fluids back to the body surface

The representative formula for cool-dryness is Xing Su San — and the herbs in it are all warm-natured.

💬 Note from Doctor Luo: The “Su” in Xing Su San is perilla leaf (zi su ye) — warm, dispersing, it spreads the qi mechanism outward to the body surface and makes it sweat; paired with apricot kernel (xing ren); then paired with Er Chen Tang (Two Aged [Ingredients] Decoction) — pinellia and poria, which resolve phlegm, and pinellia is warm; add qian hu (peucedanum) and platycodon (jie geng), which spread the lung qi and regulate qi to stop cough; add a little ginger and jujube, a little tangerine peel (chen pi), to regulate the qi mechanism and get it moving. The herbs chosen are basically all warm-natured — they get the qi mechanism flowing, let the phlegm scatter, and let the fluids return to the body surface — this is a very effective formula. The corresponding patent medicine is Xing Su Zhi Ke Granules (Xing Su Zhi Ke capsules and the like — available in pharmacies). If you cannot buy it, you can put together a simple version yourself: use a bit of perilla leaf, some tangerine peel, and optionally some crushed apricot kernel boiled together; generally perilla leaf with tangerine peel and two slices of ginger, drunk as a tea, will also do.

Doctor Luo especially reminds us: quite a lot of people right now actually have cool-dryness — white phlegm, slightly sticky, with a bit of aversion to cold; cold-pattern signs predominate.

Nine: warm-dryness: the scorching midday dryness of late autumn

As autumn continues, another situation appears — warm-dryness (wen zao): very hot at midday, very cool morning and evening. Morning and evening you wear thick clothes; at noon the sun beats down and you sweat. Clear skies, high clouds, the sun blazing — and the dryness pathogen arrives.

💬 Note from Doctor Luo: What does warm-dryness look like? The tongue is red — many people have very thin or no tongue coating, the tongue is red with cracks on it; easy to have fever, mildly afraid of wind, headache, little sweating — somewhat similar to cool-dryness, also with dry throat and dry nose, dry inside; dry cough with little phlegm; thirst — but wanting COLD drinks, only cool drinks feel comfortable (people with cool-dryness feel uncomfortable drinking cold and need something hot); the pulse is fast (shu mai). How to judge? You can actually judge entirely from the tongue.

Doctor Luo also told a real case:

💬 Note from Doctor Luo: The day before yesterday I was regulating an elderly relative back home — the tongue was very red, and she said she slept badly, was irritable, could not sleep well, had no strength in her body, all kinds of problems, and kept coughing. I looked at the tongue: very red, no coating — I said, we must quickly nourish yin, this is warm-dryness. How to treat it? Use the classic formula Qing Zao Jiu Fei Tang (Clear Dryness and Rescue the Lungs Decoction).

Ten: Qing Zao Jiu Fei Tang: Yu Jiayan’s famous formula — Doctor Luo used it to rescue an elderly patient

What is the thinking behind Qing Zao Jiu Fei Tang? It is “moisten” — using moistening methods to nourish yin and resolve dryness.

💬 Note from Doctor Luo: In the formula there is donkey-hide gelatin (e jiao) (moistens), raw gypsum (sheng shi gao) (clears heat), mulberry leaf (sang ye) (clears deficient heat), hemp seed (huo ma ren) (moistens dryness — it has oils), loquat leaf (pi pa ye) (cool, descends lung qi), ophiopogon (mai dong) (moistens), apricot kernel (descends lung qi), plus a little ginseng to support upright qi — that is the general idea. This is a very classic ancient formula, from Doctor Yu Jiayan (a famous Qing-dynasty physician) in his Yi Men Fa Lü (The Laws of the Medical Lineage). After the elderly lady drank it, she said it was simply too comfortable — she kept drinking it, several rounds, several courses, very comfortable. She said this formula was miraculous, immediate results — her sleep got better, her lungs felt comfortable, and the cough disappeared. These classic ancient formulas, when you use them precisely, work beautifully.

Eleven: illness does not follow the textbook — cold outside with dryness inside: scatter and moisten at the same time

At this point everyone will ask: so am I cool-dryness or warm-dryness? Doctor Luo says Chinese medicine sometimes makes the mistake of dividing illnesses too sharply — just like colds are divided into wind-cold and wind-heat, and everyone agonizes over “am I wind-cold or wind-heat?”

💬 Note from Doctor Luo: Illness is absolutely not that simple. Some cases are very classic — this elderly lady was pure warm-dryness, so nourishing yin worked; but sometimes the two exist simultaneously. For example, in the current post-COVID residual situation, many people went through high fever with fluids depleted and damaged, and at the same time caught a little cold — cool-dryness on the outside, warm-dryness on the inside, because yin fluids are insufficient. I often say most colds are cold outside with heat inside — why don’t wind-cold and wind-heat stay separate? Many people have both cold outside and heat inside. The dryness pathogen works the same way: many people may have cool-dryness outside (caught cold) + warm-dryness inside (internal heat, insufficient fluids) at the same time.

So what to do? Doctor Luo gives his experience:

💬 Note from Doctor Luo: Use perilla leaf and tangerine peel to scatter the exterior cold and moisten a little; on the inside you can use a bit of donkey-hide gelatin, ophiopogon, asparagus root (tian men dong), and glehnia (sha shen) to moisten. At the same time you can nourish the blood — blood and fluids share the same source; when blood is replenished, fluids follow naturally. Use a little angelica (dang gui) and Yu Ling Gao (Jade Spirit Paste). Then use some wumei and white sugar water — smoked plum with white sugar, the sour-sweet yin-generating (suan gan hua yin) method — it supplements yin, blood, and fluids, and moistens dryness. Supplement as much as possible on the inside; on the outside use tangerine peel and perilla leaf to scatter the cold. Even for stubborn cases, I add a little forsythia (lian qiao) and honeysuckle (jin yin hua) — lightly clear the pathogen, and the body slowly recovers.

Twelve: daily small remedies — donkey-hide gelatin, wumei sugar water, Yu Ling Gao, tangerine peel and perilla leaf tea

Some friends say: Teacher, what you explain is too complicated — I just cough every day, have a little phlegm, an itchy throat, dryness. Doctor Luo says: we are not treating that little bit of phlegm or that little cough — we are regulating the body.

💬 Note from Doctor Luo: After the great battle, if you can nourish yourself, that is excellent. Supplement what? Those with qi deficiency can supplement qi; and many people have dryness — the body’s fluids have been consumed too much. Friends whose conditions allow can get a little donkey-hide gelatin, or drink a bit of donkey-hide gelatin oral liquid — gelatin’s dryness-moistening effect is quite good. You can drink wumei sugar water — that is, sour plum drink, but brew it at home yourself: boil smoked plum with white sugar and drink that soup — very good. You can drink Yu Ling Gao — it nourishes the blood; no need for much, one cup a day, one small pack a day will do. This is supplementing from the angle of blood and yin.

How to scatter the exterior cold?

💬 Note from Doctor Luo: Another thing: every day take one slice of tangerine peel (no need for much — one slice is enough), take a small handful of perilla leaf, boil them in water and drink to scatter things. If you can buy Xing Su Zhi Ke Granules, even better — drinking a little is fine too. Generally use small amounts of both tangerine peel and perilla leaf; dispersal does not need to be heavy. Tangerine peel is the most crucial — tangerine peel is warm; it spreads the lung qi outward; one slice steeped in water, drunk as tea. This way the inside is moistened, the outside cold is scattered, and the body can be regulated back to health very well.

Closing: long COVID is nothing to fear — the ancestors already wrote down the answers

Doctor Luo says the key point of today’s talk is: in the past everyone divided warm-dryness and cool-dryness very finely and very clearly, but illness does not come according to the textbook — when the weather is very typical, the classic methods (one Xing Su San, one Qing Zao Jiu Fei Tang) work immediately; but after a serious illness drains you and the outside weather keeps changing unpredictably, complex situations of cold outside with dryness inside often appear. His experience: add a little exterior-cold-scattering medicine outside, add dryness-moistening medicine inside — this combination is especially effective.

💬 Note from Doctor Luo: The symptoms remaining after COVID — overseas they are called “long COVID” — some people suffer for a very long time; some people really cannot go back to work. Westerners are unlucky, because they do not have Chinese medicine; the ancients left them nothing like this. I said long ago: the so-called “long COVID,” in the eyes of Chinese medicine, is something we are especially good at — the various small formulas we use can regulate it back. Our ancestors long ago summarized all of this. So do not be afraid; study Chinese medicine slowly, understand it gradually: the big battle is over; cleaning up the battlefield is a small matter for Chinese medicine. Tomorrow we will continue talking about post-COVID body regulation. Thank you all for listening — see you tomorrow!

What to take away

The dryness pathogen (zao xie) explains most post-COVID residuals: dry throat that always wants to cough, a little white sticky phlegm, stuffy nose — one of the six excesses, acting most on people whose fluids are already depleted.
Know the two kinds of autumn dryness: cool-dryness (liang zao) — early autumn, contracting qi, fear of wind and cold, white phlegm, pale dry tongue → disperse with warming herbs (Xing Su San / Xing Su Zhi Ke Granules / perilla leaf + tangerine peel tea); warm-dryness (wen zao) — late autumn midday heat, red cracked tongue, thirst wanting cold drinks, dry cough, rapid pulse → moisten and nourish yin (Qing Zao Jiu Fei Tang).
Dryness injures the lungs first — the delicate organ entered via mouth and nose; the lungs and large intestine are paired, so dry stools belong to the same picture.
Blood and fluids share the same source: blood deficiency borrows fluid from the tissues — nourish the blood (angelica, Yu Ling Gao) and the fluids follow.
Most post-COVID cases are mixed: cool-dryness outside + warm-dryness inside — scatter the exterior (perilla leaf, tangerine peel) while moistening inside (gelatin, ophiopogon, asparagus root, glehnia), plus wumei sugar water for sour-sweet yin generation.
Daily small remedies: donkey-hide gelatin or its oral liquid, homemade wumei sugar water, one small pack of Yu Ling Gao daily, and a slice of tangerine peel with a handful of perilla leaf steeped as tea.
Long COVID is a small matter for Chinese medicine: the ancestors already wrote the answers; illness does not follow the textbook, so adjust the method to the person and the season.

Compiled from Doctor Luo Dalun’s health lecture (post-COVID recovery series: the dryness pathogen chapter).