Here is a set of complaints men rarely put in the same sentence, because they seem to have nothing to do with each other.
Knuckles that crack and bleed a little by November. A nose that is dry, or bleeds, first thing in the morning. And bowels that have quietly slowed down, which almost nobody mentions to anyone.
Chinese medicine has put those three in the same file for centuries. The file is called 秋燥 (qiū zào), autumn dryness.
What I find most interesting about it is not the diagnosis. It is the paper trail. Because the founding text of Chinese medicine left it out, and a physician in 1658 stood up and said so.
An Audit of the Classics
The Huangdi Neijing contains a famous list called the nineteen disease mechanisms, 病机十九条, in Su Wen chapter 74. It sorts illness by its driving influence: wind, cold, damp, heat, fire.
Dryness is not on it.
Worse, Su Wen chapter 5 says 秋伤于湿，冬生咳嗽. Injured by damp in autumn, you cough in winter. Damp. In the season later physicians would call the driest of the year.
In the Jin dynasty, Liu Wansu (刘完素) quietly added a twentieth line: 诸涩枯涸，干劲皴揭，皆属于燥. Everything rough and withered, dry and stiff, cracked and peeling, belongs to dryness. Read that with your hands in mind in late autumn. It is a better description of chapped skin than most dermatology leaflets.
Then Yu Chang (喻昌) went further. In his 1658 essay On Autumn Dryness (《秋燥论》), he wrote the sentence I think every tradition should have somewhere in its canon:
《内经》病机一十九条，独遗燥气. Of the Neijing’s nineteen mechanisms, dryness alone was left out.
He argued the “damp in autumn” line was a misreading that generations of scholars had simply copied without checking, and he rewrote the sequence: wind in spring, heat in summer, damp in late summer, dryness in autumn, cold in winter.
I tell this story because it is the part of Chinese medicine that rarely gets told. People assume the tradition is a fixed text handed down unquestioned. It is not. At its best, it is a long argument between physicians who looked at their patients, looked at the book, and wrote down where the book was wrong.
Why the Top and the Bottom Go Together
The traditional explanation runs like this. The Lung, autumn’s organ, takes fluid and spreads it upward and outward like a fine mist, to the skin, nose and throat. It also sends fluid down to the Large Intestine, its paired organ, keeping the stool moist enough to move.
When dryness wins, both ends dry out at once. Skin, nose and throat at the top. Hard, slow stools at the bottom.
That is not a modern explanation. But the grouping is useful, and the modern science on dry air mostly points the same direction.
What Dry Air Actually Does
To the airway. A 2024 review in the International Journal of Hygiene and Environmental Health pulled together the recent office studies and laboratory work on indoor humidity. Its conclusion: dry indoor air goes with more eye and airway irritation, slower mucociliary clearance (the cilia that sweep mucus, and whatever it has trapped, out of the airway), and a less efficient immune defense at the airway lining. A 2022 study of office buildings published in Indoor Air found the same pattern in real workplaces. Low humidity was common, and it went with more reported symptoms in both men and women.
Much of the mechanism work behind this still comes from animal and laboratory studies, and humidity is only one of several reasons respiratory infections peak in winter. I would not overstate it. But it gives some mechanical meaning to an old idea that dryness weakens the Lung’s defense.
To the skin. In a 2023 study in Skin Research and Technology, researchers in Korea sat healthy adults in an ordinary heated indoor room in January and February, when the air was at its driest. After just six hours, their skin measurements had already shifted. A 2025 laboratory study on lab-grown human skin suggests one reason why: an hour of dry air was enough to raise water loss through the outer layer and reduce the proteins that seal the gaps between skin cells. Then the heating goes on at home, and the air in your bedroom can end up drier than the air outside. Keeping indoor humidity around 30 to 50% is the usual guidance.
What Has Evidence and What Is Just Tradition
Chinese dietary therapy has a whole category for this, 润燥, “moistening dryness.” Some of it has decent modern evidence. Some of it is good tradition and nothing more. I would rather sort it than sell it.
Honey, for a dry cough: reasonable evidence, modest certainty. A 2023 systematic review in the European Journal of Pediatrics gathered the trials published since the last Cochrane review. It found low-quality evidence that honey may ease cough symptoms and improve sleep more than cough medicine, placebo or no treatment. Those were children, not men, and the authors called for better trials. But it is more than most home remedies can show. Never give honey to a baby under a year old.
Prunes, for slow bowels: modest evidence, with a better-supported alternative. In October 2025 the British Dietetic Association published the first evidence-based dietary guidelines for chronic constipation in adults, built on four systematic reviews covering 75 randomized trials. Prunes made the list, at around eight to ten a day in the trials behind it. The footnote: kiwifruit came out stronger. Two or three a day performed about as well as a fiber supplement, with fewer side effects such as gas and bloating. The same guidelines also found too little evidence that a general high-fiber diet helps constipation specifically, which surprises most people.
Pear, for a dry throat: tradition strong, evidence thin. A steamed pear with a little honey is what Chinese families reach for first. I haven’t found good human trials showing pear itself does anything for a cough. It is warm, soft and hydrating. Eat it for that.
Sesame, walnuts, figs: sensible. Traditionally used to moisten the bowel. The modern explanation is fat and fiber, which is to say ordinary nutrition working as expected.
The Things Making It Worse
Long, very hot showers. Heated rooms with no humidity. Salty, crunchy snacks as a nightly habit. A lot of alcohol, which is drying and diuretic. And, in the tradition’s view, late nights, which are said to burn through the body’s moistening reserve.
And One Thing Not to Blame on the Weather
Autumn dryness is common. It is not an explanation for everything.
A change in bowel habit that persists for weeks, especially with blood, weight loss or fatigue, needs a doctor, not a bowl of prunes. Colorectal cancer has been rising in adults under fifty, and men are often the last to report the symptom. The same goes for a cough lasting more than three weeks, coughing blood, or nosebleeds that are heavy or frequent.
Yu Chang’s contribution was refusing to let a respected text explain away what he could see. That habit is worth keeping for your own body too.
Sources
Indoor air humidity revisited: impact on acute symptoms, work productivity, and risk of influenza and COVID-19 infection. International Journal of Hygiene and Environmental Health, 2024;256:114313.
Indoor humidity levels and associations with reported symptoms in office buildings. Indoor Air, 2022;32(1):e12961.
Effects of winter indoor environment on the skin: unveiling skin condition changes in Korea. Skin Research and Technology, 2023;29(6):e13397.
Effect of low humidity on the barrier functions of keratinocytes in a reconstructed human epidermal model. International Journal of Cosmetic Science, 2025;47(3):523-534.
Honey for acute cough in children: a systematic review. European Journal of Pediatrics, 2023;182(9):3949-3956.
Dimidi E, et al. British Dietetic Association guidelines for the dietary management of chronic constipation in adults. Journal of Human Nutrition and Dietetics, 2025;38(5):e70133.
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