The Medicine Circulates the Whole Body — So Why Does It Work Only Where It Hurts?

"How does a medicine I swallow find my aching knee?"

When I get this question in the clinic, I pause for a moment. It is because it is a good question. Medicine enters through the mouth, passes the stomach and intestines, rides the blood, and circulates evenly through the whole body. It does not go only to the knee. It goes to the fingertips, and to the roots of the hair.

And yet the effect appears at the knee. Why is that?

The common answer is "the medicine finds where it hurts." I do not use this explanation. The medicine does not know the way. The medicine is not searching for anything.

My answer lies on the opposite side. What "goes there" is not the medicine — what has changed is the site.

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What this article means to say, in one sentence

Disease arises not because a part has broken, but because the environment has changed.
Medicine behaves differently in that changed environment.
That is why the medicine's effect shows not throughout the body, but at the site that has broken down.

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First, the widespread misconception

Common thought	What I understand
The medicine finds where it hurts	The medicine spreads evenly through the whole body. It does not know the way
More medicine accumulates where it hurts	It may accumulate, but more than that, the medicine's properties change at that site
The strength of the ingredient decides the effect	The same ingredient acts differently depending on the environment
A good medicine improves the whole body	A good medicine restores the axis that has broken down. It leaves the rest untouched

What is different about a site that has broken down?

When some site of the body has hurt for a long time, that site becomes different in its very environment from a healthy site. Before the cells break down, the environment changes first.

Let me look at what changes, one at a time.

The blood vessels loosen.
At a site where inflammation has lingered long, the seams of the vessel walls become loose. Substances that would ordinarily not leave the vessel easily seep out at that site.

It tilts toward acidity.
That site is short on oxygen, and metabolic waste piles up. So it becomes more acidic than its surroundings. This is the heart of the story to come.

The way out becomes blocked.
The flow that clears away substances that have entered (the lymph and veins) slows down. It becomes a site that is easy to enter and hard to leave.

The receiving side grows sensitive.
The number and sensitivity of the receptors that receive signals change. It responds differently to the same signal.

   Healthy tissue                  Broken-down tissue
 ─────────────────            ─────────────────
  Vessel seams tight           Vessel seams loose
  Acid-base balance kept       Tilts toward acidity
  Smooth entry and exit        Easy to enter, hard to leave
  Receptor response stable     Receptors sensitive / dulled
 ─────────────────            ─────────────────
        ↓                             ↓
   Medicine passes through     Medicine lingers, its properties change

Acidity is the key

Here let me go a little deeper. It looks difficult, but the principle is simple.

A large share of medicinal ingredients carry the property of an acid. Such substances become electrically closer to neutral when their surroundings are acidic. A substance that has become closer to neutral passes more easily through the fatty barrier that is the cell membrane.

So it goes like this.

1. The broken-down site is more acidic than its surroundings
2. The medicinal ingredient enters the cell more easily at that site
3. The inside of the cell is relatively less acidic → the ingredient that entered takes on an electrical charge again
4. A charged substance can no longer cross the cell membrane → it is trapped

It is a structure that is easy to enter and hard to leave. The medicine did nothing, and yet the environment of that site holds the medicine.

Onto this overlap the loosened vessels and the blocked drainage mentioned earlier. Easy to seep in, easy to be trapped, hard to leave. The three meet at one site.

And so the low concentration of herbal medicine is explained

In another article I have written about the paradox of concentration in herbal medicine. The story was that the concentration at which herbal ingredients remain in the blood is, by the standards of modern drugs, astonishingly low — and yet the body clearly responds.

Adding the view of this article loosens that paradox a little.

The concentration being low across the whole blood and the concentration being low at the broken-down site are different stories. The concentration measured from drawn blood is the average of the whole body. Even if the average is low, at a site whose environment has changed, the ingredient lingers and gathers.

Not pushing the whole body evenly, but acting only at the site where it is needed — I see this as one reason herbal medicine has carried relatively little burden even with long-term use.

But this is not all of it

If I stop here, it is only half. I am wary of the temptation to translate every disease into the language of acid-base and pressure.

The axes that break down run in many directions.

Axis	When this axis breaks first
Physical axis	Tension, stress, and pressure accumulate, and the tissue's properties change
Chemical axis	The balance of acid-base, enzymes, and ions is shaken
Metabolic axis	The very work of producing energy breaks down
Immune axis	The immune baseline of the gut mucosa is shaken, and the whole body shakes with it
Time axis	The same stimulus splits in its result by how fast, and over how long, it accumulated
Nervous-system axis	The autonomic nerves and pain circuits amplify on their own
Circulatory axis	The flow of coming in and going out slows down
Endocrine axis	Regulating hormones, cortisol among them, are depleted

There is no higher or lower among these axes. The axis that breaks first differs for each disease. When one breaks, the rest are merely shaken in a chain.

For example, in a person whose long-standing diarrhea has drained their energy and left their hands and feet cold, the language of pressure hardly appears at all. The immune function of the gut mucosa was shaken first, absorption broke down, and so energy metabolism collapsed, peripheral blood flow decreased, and finally the adrenal glands were depleted. What this person needs is not to lower pressure but to stabilize the gut's immunity and revive absorption.

Conversely, in a person whose lower-abdominal pressure has risen so that the groin ligament is pulled and a nerve is pressed, hurting at the slightest brush, the physical axis is the protagonist.

Reading which axis broke first — I believe that is what clinical practice is.

What treatment does

Seen this way, the goal of treatment changes too.

It is not the work of replacing a part. It is the work of restoring the environment and helping the body stabilize its own responses.

• Stiffened tissue must be released so that its properties change — not cracked open — if it is not to slip back
• A site where flow is blocked should not be forced open; it must be given a reason to flow
• A nerve that has grown sensitive should not be pressed off; it settles only when there is nothing left to startle it

The same is true of medicine. Not a medicine that works in place of the body, but a medicine that creates an environment in which the body can work again — that is what I use.

What must be left honestly stated

It is right that I state how much of what I have said so far is established, and where my own interpretation begins.

What is established

• That vascular permeability rises in tissue with long-standing inflammation
• That such tissue tilts toward acidity relative to its surroundings
• That the passage of weakly acidic substances across the cell membrane changes in an acidic environment
• That many herbal ingredients are activated through the metabolism of gut microbes

What is not yet established

• How large a role these principles actually play in a human body, at the low concentrations of herbal medicine
• How much each of the above mechanisms contributes

Most of the evidence comes from test tubes and animals. There is not yet enough research directly confirming all of this in humans. I use this not as settled fact, but as the frame that best explains what I have observed in clinical practice.

And there are many diseases this frame does not explain. To say that a disease herbal medicine cannot help cannot be helped is, I think, the minimum honesty I can offer a patient.

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When a patient asks me, "Why does this medicine work for me?", instead of naming an ingredient, I mean to say this.

The medicine did not find your knee. Your knee had changed, and so the medicine behaved differently there.

So even after treatment ends, the work of protecting that site's environment remains. If there is a disease that returns when you stop the medicine, it is not that the medicine was insufficient — it is that the environment was still the same.