The kidney is the prenatal root; the spleen is the postnatal root (先天之本，后天之本). These eight characters are the general programme of Chinese medicine, both in nurturing life and in prescribing.
| Root | What it governs | What it is like |
|---|---|---|
| Kidney · the prenatal root | Stores yuanqi (元气), kidney essence (jing, 精), and the fire of the gate of life | A warehouse — the stock is the family capital |
| Spleen · the postnatal root | Transforms the essence of the five grains; the source of qi and blood | A processing plant — producing and shipping every day |
In this warehouse the goods arrive in two consignments, and they must be kept distinct.
This explains three familiar things. Someone born with a thin foundation who cares for himself well still lives long and lives well, because he keeps making deposits. Someone born with a thick foundation who stays up late, indulges his desires, and overworks withdraws more than he saves, and by middle age the bottom is visible. And nourishing spleen and stomach is, in essence, restocking the kidney — with a good spleen, the warehouse is not too empty even in old age.
This is the most easily misunderstood point of all: drugs cannot replenish the yuanqi of a person.
If drugs could replenish yuanqi, emperors would not have died so young; they had every precious tonic and herb. Apart from a few nourishing substances that are both medicine and food, most medicines — plant, mineral, or the chemical compounds of today — carry no “life force” of their own. Their work is to mobilise and draw out the yuanqi still in you, to repair what is broken, blocked, or inflamed.
In the language of the warehouse: medicine is not a porter carrying goods in; it is the foreman — standing at the gate of the plant shouting “put your backs into it”. The soldiers are still your soldiers, the grain still your grain, and grain does not multiply out of nothing.
This is why the long ill, the elderly, and women after childbirth or surgery cannot be attacked or tonified hard from the outset. Their yuanqi is no longer sufficient to be mobilised; the harder you drive it, the emptier they become. What is needed first is that they can eat and sleep — restart the plant.
Yuanqi comes from one place only: the essence of the five grains, plus yang qi.
Two things here, neither dispensable: grain and fire. Eating without transforming is food stagnation and phlegm-damp — material piled at the door with the machine off. Fire without rice is empty fire burning the person — the machine running dry, fuelled by yourself.
This is why spleen and stomach are the root of health. When they fail, the plant shuts down: however expensive the food and however diligent the tonics, the goods are only stacked outside the door and never reach the warehouse.
Because for a tonic to become your yuanqi it must pass the gate of the plant and then enter the warehouse: the stomach must be able to receive, the spleen to transform, the kidney to store — all three passes, none dispensable.
In most people today these three passes are blocked: dinner too late, cold drinks without pause, ceaseless brooding, late nights that damage yang. The plant is already short of fire and its machinery rusting; pile in ginseng, deer antler, and donkey-hide gelatin and it only congests into dampness, turns to heat, and becomes phlegm — leaving mouth ulcers and a body heavy and dull.
Those who truly know how to tonify subtract first and tonify after: dinner down to seven-tenths, the iced things stopped, enough sleep — until the tongue coating thins and the appetite returns. The machine is running again, and one bowl of foxtail millet gruel does more than a box of tonics.
The old saying — “tonifying with medicine is inferior to tonifying with food, and tonifying with food is inferior to tonifying with sleep” — is about exactly this order.
Why should daily rhythm follow the sun? See a person as a tree and it is all clear.
A tree through a year: buds in spring, leaves in summer, drawing in during autumn, roots stored in winter. A person through a day follows the same circle.
↑ Tap a season to see the four ways a person grows through one day
In spring the tree pushes its buds through the bark with a force that moves upward. In the morning a person has the same force: liver qi rising.
So at daybreak: take in light, get up, move about, and let yang qi go outward as it will. Staying in bed is pressing the bud back into the branch — the qi of the day is pent from the start.
Corresponds to: 5–9 a.m. — rise, walk, eat a warm breakfast.
In summer the leaves open fully and photosynthesise for all they are worth: the most outward-turned time of the year. So it is for a person from late morning to afternoon: yang qi is on the surface; it is time to work, and time to sweat.
Do not fear the heat, do not simply hide in air conditioning. If the pores do not open when they should, summer heat and dampness are shut inside, and autumn brings cough and wheeze.
Corresponds to: 9 a.m.–3 p.m. — concentrate, work, stop at a light sweat.
In autumn the tree stops putting out new leaves and draws its nourishment back into trunk and branch. In the evening a person should gather the spirit: do less, eat slowly, contend with no one, and do not hold the meetings that need not be held.
To be exercising hard, arguing loudly, or scrolling furiously at this hour is to force open what should be closing; sleep at night will be shallow.
Corresponds to: 5–9 p.m. — settle the mind, warm water, few words.
A winter tree looks empty, but underground the roots are quietly growing. It has drawn all its strength back in.
So it is with a person at night: sleep is not “wasted time”, it is root growth. That sleep nourishes kidney essence and the yuanqi of tomorrow. Staying up late is setting the winter tree alight to roast its leaves.
Corresponds to: after 9 p.m. switch off and close the eyes; by midnight at the latest.
No instruments needed. Look at these:
Nurturing life in Chinese medicine is not a return to antiquity but a return to position: putting a person back from “fighting the body” to “following the way of heaven”.
Medicine assists upright qi, practice nourishes it, external treatment clears its path.
The weeds are never all pulled, but on sun-dried wood nothing grows.