YOON CLINIC FORMULA ARCHITECTURECASE STUDY 001: LING GUI ZHU GAN TANG

How We Built the Formula Architecture of Fu Ling, Gui Zhi, Bai Zhu, and Gan Cao

1. STARTING POINT: A FORMULA IS NOT A LIST OF HERBAL ACTIONS

We did not begin by memorizing Ling Gui Zhu Gan Tang as:

• Fu Ling: promotes urination

• Gui Zhi: warms Yang

• Bai Zhu: strengthens the Spleen

• Gan Cao: harmonizes the formula

This conventional explanation lists the traditional functions of each herb but does not adequately answer the more important questions:

Why are Fu Ling and Gui Zhi used together?

Why is Gan Cao required?

What changes when Bai Zhu is added?

Why do epigastric discomfort, palpitations, upward rushing, and dizziness coexist within one formula?

What physiological state does this formula address in a contemporary patient?

We therefore chose not to begin with the completed formula. Instead, we first examined the smallest recurring herb combinations and the sequence in which additional herbs modified the clinical pattern.

The basic method was:

Recurring herb combination

→ Recurring clinical findings

→ Inference of the minimal unit’s function

→ Identification of symptoms added by each additional herb

→ Inference of the added herb’s incremental function

→ Comparison with modern pathophysiology and pharmacology

→ Construction of the formula’s systems-level function

2. FIRST DISCOVERY: FU LING–GUI ZHI IS A RECURRING FORMULA FAMILY

When formulas are compared through the Lei Ju Fang approach, Fu Ling and Gui Zhi repeatedly appear together.

Examples include:

• Fu Ling Gui Zhi Gan Cao Tang

• Ling Gui Zhu Gan Tang

• Ling Gui Gan Zao Tang

• Fu Ling Gan Cao Tang

Related structures within the Wu Ling San family

Other Fu Ling–Gui Zhi combinations

This repetition is unlikely to represent incidental coadministration.

Across these formulas, several findings recur:

• Palpitations

• Pulsation below the heart or below the umbilicus

• Upward rushing

• Dizziness

• Running-piglet sensations

• Anxiety and agitation

• Symptoms related to changes in posture

• Symptoms that fluctuate with fluid status

This suggested that Fu Ling and Gui Zhi do more than simply “remove water and warm the body.”

They may constitute a minimal functional unit for a pathological state in which changes in fluid status become linked to palpitations, upward rushing, and dizziness.

3. THE ORIGINAL PATHOLOGICAL MODEL: PALPITATIONS AFTER SWEATING

The sequence of formulas and clauses in classical texts suggests that many Ling Gui Gan-type formulas address palpitations and neurological symptoms arising after an infectious illness, particularly following sweating or the inappropriate use of diaphoretic treatment.

A modern working interpretation is:

Infection and fever

→ Sweating or excessive diaphoresis

→ Changes in intravascular fluid and electrolyte conditions

→ Reduced venous return and effective circulating volume

→ Compensatory increase in heart rate and vascular tone

→ Palpitations, upward rushing, dizziness, anxiety, and agitation

An important implication is that the patient’s anxiety may not be the primary cause of the palpitations.

When circulating volume and blood-flow distribution become unstable, heart rate and vasoconstriction may increase. The patient may then experience this physiological compensation as:

• Palpitations

• A sensation of rising into the chest

• Lightheadedness

• Uneasiness or fear

We therefore provisionally defined the palpitations of the Ling Gui Gan family as:

“An excessively amplified cardiovascular and autonomic compensatory response to changes in fluid and circulatory status.”

4. GUI ZHI GAN CAO TANG AS THE MINIMAL REGULATORY UNIT

Gui Zhi Gan Cao Tang can be viewed as the smallest formula structure addressing palpitations and urgent chest sensations after sweating.

Gui Zhi

→ Regulates vasomotor behaviour and the direction of upward rushing

Gan Cao

→ Dampens urgent palpitatory and chest responses

At this stage, neither Fu Ling nor Bai Zhu is present.

The central problem is therefore not yet fluid retention. It is closer to:

Sweating or a change in fluid state

→ Excessive cardiovascular and vasomotor compensation

→ Palpitations, upward rushing, and chest urgency

We therefore defined the Gui Zhi–Gan Cao pair as:

“A minimal regulatory module that reduces vasomotor instability while damping the abrupt palpitatory and autonomic response generated by that instability.”

5. HOW WE INFERRED THE FUNCTION OF GUI ZHI

Gui Zhi could initially be described in traditional terms as an herb that warms the channels, supports Yang, and redirects upward rushing.

However, a more specific modern physiological model was needed.

Cinnamaldehyde, a major constituent associated with cinnamon twig, has shown vascular smooth-muscle relaxation and calcium-regulating effects in preclinical studies.

The statement that Gui Zhi “directly dilates the capillaries,” however, is anatomically imprecise.

Capillaries contain little or no vascular smooth muscle. Peripheral resistance and tissue blood flow are regulated primarily at the level of small arteries, arterioles, and precapillary resistance vessels.

The function of Gui Zhi was therefore revised as:

“It reduces excessive resistance-vessel tension, adjusts central-to-peripheral blood-flow distribution, and thereby reduces centrally concentrated pressure sensations, upward rushing, and compensatory palpitations.”

In compressed form:

GUI ZHI

= Vasomotor Pressure Redistribution

= Regulation of vascular tension and pressure–flow distribution

This model also helps explain why the following findings can coexist:

• Cold hands and feet

• Upper-body flushing

• Palpitations

• Upward rushing

They may represent different expressions of the same unstable vasomotor system.

6. HOW WE INFERRED THE FUNCTION OF GAN CAO

Gan Cao appears in so many formulas that describing it merely as an herb that “harmonizes the formula” obscures its clinical function.

When formulas in which Gan Cao has a central role are compared, several patterns recur:

• Palpitations and visible pulsation

• Urgency

• Cramp-like muscular contraction

• Abdominal tension

• Chest instability

• Emotional urgency

• Rapid amplification of multiple symptoms

In Gui Zhi Gan Cao Tang, palpitations are prominent.

In Shao Yao Gan Cao Tang, acute muscular contraction and cramping are prominent.

In Gan Mai Da Zao Tang, emotional and behavioural urgency are prominent.

The common feature appears to be:

“An excessive and urgent amplification of a physiological response.”

Potential modern correlates may include modulation of:

• Excessive smooth- or skeletal-muscle contraction

• Inflammatory stimulation

• Visceral sensory input

• Stress-response amplification

However, there is insufficient evidence to claim that Gan Cao treats every form of urgency through one specific autonomic receptor or molecular mechanism.

We therefore adopted the following functional description:

GAN CAO

= Acute Response Damping

= Dampening of rapidly amplified palpitatory, muscular, visceral, and stress responses

7. WHAT CHANGES WHEN FU LING IS ADDED?

When Fu Ling is added to Gui Zhi–Gan Cao-based structures, the following findings become more prominent:

• Pulsation below the heart or below the umbilicus

• Dizziness

• Symptoms fluctuating with fluid status

• Oedema or changes in urination

• Anxiety and agitation

• Posture-related symptoms

• A clinical connection between palpitations and fluid disturbance

This suggested that Fu Ling is not simply a diuretic.

Instead, it may address the coupling between fluid-state instability and neurocirculatory symptoms.

A possible modern sequence is:

Imbalance among fluid intake, sweating, retention, and excretion

→ Mismatch between effective intravascular filling and tissue fluid

→ Renal water-retention signalling plus autonomic circulatory compensation

→ Palpitations, dizziness, anxiety, and oedema

Preclinical studies of Fu Ling-related preparations have reported effects involving the AVP–V2 receptor–AQP2 axis.

However, these findings do not explain the entire classical indication of Fu Ling, nor do they directly prove that Fu Ling relieves palpitations and dizziness through this mechanism in human patients.

Its role was therefore defined as:

“Regulating fluctuations in fluid retention, excretion, and distribution so that changes in fluid status are less likely to become amplified into palpitations, dizziness, and anxiety.”

In compressed form:

FU LING

= Fluid–Neurocirculatory Coupling Regulator

= Regulation of the connection between fluid-state changes and neurocirculatory symptoms

8. IDENTIFYING THE LING GUI GAN PATIENT PHENOTYPE

Classical clauses and formula composition alone were not sufficient to identify the contemporary patient most likely to fit this formula family.

We therefore extracted recurring clinical observations regarding the physical appearance, constitution, and behavioural response pattern of Ling Gui Gan-type patients.

BODY BUILD

Body weight is often normal or slightly low.

Physical stamina is usually not exceptionally strong.

The patient does not necessarily appear severely deficient, but the physiological reserve often seems limited.

SKIN

The skin is not simply pale.

It often appears thin, translucent, and visibly reactive.

Flushing and superficial vascular changes are easily observed.

This contrasts with the darker, drier, denser, and more compact skin often associated with Ma Huang-type patients.

TEMPERATURE AND SWEATING

The patient often feels cold.

The hands and feet are frequently cold.

Sweating tends to occur relatively easily.

When the patient is currently depleted, sweating may be followed by fatigue, coldness, palpitations, or lightheadedness rather than a refreshed feeling.

This is not absolute.

A healthy, physically trained person with the same constitutional pattern may exercise regularly and feel refreshed afterward.

EMOTIONAL PATTERN

The patient tends toward anxiety, worry, agitation, and easy startling.

This is not primarily the aggressive, irritable, or tense sensitivity seen in other formula patterns.

The impression is closer to a cautious, easily alarmed “rabbit-like” response.

The patient often detects internal bodily changes quickly.

STIMULUS RESPONSE

Caffeine sensitivity is common.

Symptoms may be easily influenced by fasting, sleep deprivation, emotional stress, heat, or sweating.

INTAKE

Appetite is usually not excessive.

Patients often describe their appetite as normal or report being selective about food.

Many do not drink much water.

A useful clinical analogy was:

“The patient resembles the type of woman who might prefer Pilates or yoga rather than CrossFit or bodybuilding.”

This is not a literal exercise-based prescribing criterion.

It is a clinical shorthand describing body composition, skin quality, stimulus sensitivity, behavioural style, and physiological buffering capacity.

The background phenotype was compressed into four concepts:

• Low reserve

• High reactivity

• High interoceptive sensitivity

• Vasomotor instability

9. SEPARATING PHENOTYPE FROM CURRENT PATHOLOGY

A patient should not receive Ling Gui Zhu Gan Tang merely because the phenotype appears compatible.

A healthy person may have:

• Thin, translucent skin

• Cold hands and feet

• Easy sweating

• Caffeine sensitivity

• Normal or slightly low body weight

• An anxious or easily startled temperament

These characteristics indicate a background tendency, not an active formula indication.

The formula becomes relevant when the current pathological pattern includes:

• Palpitations or upward rushing

• Dizziness or instability on standing

• Epigastric or upper-abdominal discomfort

• Linked fluctuation of these symptoms

• Worsening after sweating, fasting, caffeine, or stress

• Delayed recovery after physiological stress

The phenotype therefore raises the probability of fit.

The current pathological relationship determines prescribing.

10. A CRITICAL QUESTION: WHY CAN THE FORMULA BE USED WITHOUT INFECTION OR EXCESSIVE SWEATING?

The classical prototype involved infection and excessive sweating.

Many contemporary patients, however, have neither an acute infection nor a history of inappropriate diaphoresis.

Why, then, can the same formula remain clinically relevant?

The answer emerged when sweating was reinterpreted not as a mandatory cause, but as a representative event that makes a particular physiological state highly visible.

Modern factors capable of recreating a similar intermediate state include:

• Low water intake

• Low food intake

• Caffeine

• Sleep deprivation

• Chronic stress

• Overwork

• Heat exposure

• Exercise-related sweating

• Impaired circulatory adjustment on standing

• Postprandial splanchnic blood pooling

• Gastrointestinal sensorimotor dysfunction

Different causes can converge on the same physiological condition:

Fluctuation in effective circulation and fluid distribution

→ Peripheral vasoconstriction and compensatory tachycardia

→ Palpitations, upward rushing, and dizziness

→ Reciprocal amplification through gastrointestinal instability

Classical excessive sweating was therefore understood as:

A representative trigger that clearly exposes the underlying vulnerability of a Ling Gui Gan-type patient, rather than an absolute requirement for the formula.

11. THE FIRST ERROR IN DEFINING BAI ZHU

Our initial description of Bai Zhu was:

“It promotes the movement and elimination of water retained in the gastrointestinal tract, thereby preventing recurrent epigastric stagnation.”

This statement was too specific for the available evidence.

There was insufficient support for claiming that Bai Zhu directly moves or drains water retained inside the gastrointestinal tract.

Preclinical research has suggested effects on:

• Gastric emptying

• Gastrointestinal motility

• Interstitial cells of Cajal

• Barrier function

• Inflammation

• Visceral sensory regulation

However, the findings are not unidirectional.

In some models, Bai Zhu-related preparations enhance impaired motility.

In others, they inhibit excessive contraction.

It therefore cannot be reduced to a simple prokinetic agent or a gastrointestinal water-draining herb.

At this stage, we withdrew the overextended pharmacological statement and returned to comparative formula analysis.

12. RE-EXAMINING THE INCREMENTAL FUNCTION OF BAI ZHU

We compared formulas sharing Fu Ling, Gui Zhi, and Gan Cao.

FU LING GAN CAO TANG

Sheng Jiang is added.

Pulsation below the heart, nausea, vomiting, and upward gastrointestinal movement become more prominent.

LING GUI GAN ZAO TANG

Da Zao is added.

Pulsation below the umbilicus, running-piglet sensations, and urgent rising from the lower abdomen become more prominent.

LING GUI ZHU GAN TANG

Bai Zhu is added.

The defining sequence becomes:

• Rebellious fullness below the heart

• Qi rushing upward into the chest

• Dizziness upon standing

What became clearer with Bai Zhu was not merely indigestion.

It was the following sequence:

Epigastric fullness and rebellious pressure

→ Upward propagation into the chest

→ Dizziness upon standing

Based on the comparative formula structure, we inferred the incremental function of Bai Zhu as:

“Reducing the conditions under which recurrent epigastric gastrointestinal burden propagates into chest and head symptoms.”

13. TRANSLATING THE FUNCTION OF BAI ZHU INTO MODERN PATHOPHYSIOLOGY

The classical idea of “water accumulating below the heart and rushing upward” should not be translated literally as a fixed anatomical fluid pocket.

A more plausible modern sequence is:

Impaired gastric accommodation, motility, or emptying

or

Visceral hypersensitivity

→ Disproportionate epigastric fullness and pressure after small amounts of food or fluid

→ Increased signalling from gastric stretch receptors and visceral afferents

→ Vagal, sympathetic, cardiovascular, and respiratory responses

→ Palpitations, upward rushing, anxiety, and chest discomfort

Postprandial blood-flow redistribution may add another layer:

Increased splanchnic blood flow after eating

→ Relative reduction in central blood volume and venous return

→ Compensatory increase in heart rate and vasoconstriction

→ Orthostatic dizziness in a low-reserve patient

This model provides a coherent modern interpretation of:

XIN XIA NI MAN

→ Epigastric fullness, pressure, and a sense of upward resistance

QI SHANG CHONG XIONG

→ Gastrointestinal and vasomotor signals expressed as upward rushing and palpitations in the chest

QI ZE TOU XUAN

→ Dizziness on standing due to unstable circulatory or vestibular adaptation

The final functional description of Bai Zhu became:

“Reducing the conditions in which post-intake epigastric sensorimotor instability repeatedly generates visceral and autonomic symptoms.”

In compressed form:

BAI ZHU

= Epigastric Sensorimotor Stabilizer

= Reduction of recurrent epigastric gastrointestinal instability

This remains an integrated working hypothesis derived from classical formula comparison and modern gastrointestinal physiology.

It is not a confirmed single pharmacological mechanism.

14. USING ZHI GAN CAO TANG TO DEFINE THE BOUNDARY OF THE LING GUI GAN FAMILY

Zhi Gan Cao Tang became an important comparison when the broader family of post-sweating palpitation formulas was considered.

GUI ZHI GAN CAO TANG

Vasomotor and cardiac regulation has become unstable.

LING GUI GAN-TYPE FORMULAS

Fluid-distribution instability has been added to the regulatory failure.

LING GUI ZHU GAN TANG

Epigastric gastrointestinal burden has been added to fluid–neurocirculatory instability.

ZHI GAN CAO TANG

Regulation alone is no longer sufficient.

Fluid, nutritional, metabolic, and tissue-recovery support is required to maintain stable cardiac rhythm.

Zhi Gan Cao Tang is not simply a modified version of Ling Gui Zhu Gan Tang.

Rather, it can be understood as a functional endpoint addressing the shared clinical problem of palpitations after illness or loss, but at a deeper level of depletion and rhythm instability.

This comparison clarified that Ling Gui Zhu Gan Tang primarily addresses dynamic dysregulation across:

• Fluid state

• Vasomotor control

• Autonomic compensation

• Gastrointestinal signalling

It is not primarily a formula for persistent structural arrhythmia or severe myocardial depletion.

15. FINAL FUNCTIONS OF THE FOUR HERBS

GUI ZHI

Reduces excessive resistance-vessel tension and adjusts central-to-peripheral pressure and blood-flow distribution, thereby reducing upward rushing and compensatory palpitations.

GAN CAO

Dampens rapidly amplified physiological responses such as palpitations, tension, cramping, and autonomic urgency.

FU LING

Regulates the connection between fluctuations in fluid retention, excretion, and distribution and the development of palpitations, dizziness, and anxiety.

BAI ZHU

Reduces the conditions in which post-intake epigastric sensorimotor instability repeatedly generates visceral and autonomic symptoms.

16. FROM MINIMAL COMBINATION TO COMPLETE FORMULA

GUI ZHI + GAN CAO

Regulation of vasomotor instability and urgent palpitatory responses

+ FU LING

Addition of the fluid-state–palpitation–dizziness connection

+ BAI ZHU

Addition of recurrent epigastric gastrointestinal burden as a trigger of the symptom cluster

= LING GUI ZHU GAN TANG

In pathophysiological language:

Regulatory failure

→ Fluid-distribution instability

→ Recurrent epigastric gastrointestinal burden

→ Combined palpitations, upward rushing, and dizziness

17. FINAL PATHOPHYSIOLOGICAL MODEL

BACKGROUND OF THE LING GUI GAN PHENOTYPE

• Limited physiological reserve

• High autonomic reactivity

• High interoceptive sensitivity

• Easy sweating

• Low water intake

• Cold sensitivity and cold extremities

• Thin, translucent, visibly vasoreactive skin

CURRENT PATHOLOGICAL PROCESS

Small changes in fluid state and blood-flow distribution

→ Peripheral vasoconstriction and compensatory increase in heart rate

→ Palpitations, upward rushing, anxiety, and dizziness

At the same time:

Post-intake instability in gastric accommodation, motility, or visceral sensation

→ Epigastric fullness and rebellious pressure

→ Increased visceral afferent signalling and splanchnic blood-flow redistribution

→ Amplification of chest symptoms and orthostatic dizziness

The classical sequence can therefore be translated as:

XIN XIA NI MAN

→ Epigastric fullness, pressure, and upward resistance

QI SHANG CHONG XIONG

→ Gastrointestinal and vasomotor compensation expressed as palpitations and upward rushing into the chest

QI ZE TOU XUAN

→ Dizziness on standing due to unstable circulatory, cerebral-perfusion, or vestibular adaptation

18. LOCK-AND-KEY PATTERN

The central prescribing pattern is:

Palpitations or upward rushing

+

Dizziness or instability on standing

+

Epigastric or upper-abdominal discomfort

+

The symptoms rise and fall together

The phenotype increases confidence but is not mandatory.

Phenotype without the active pathological relationship is insufficient for prescribing.

Conversely, even when the phenotype is not fully typical, the formula may still be considered when the connection among palpitations, upward rushing, dizziness, and epigastric discomfort is clear.

19. EXPECTED EARLY RESPONSE

When the formula is correctly matched, the linked symptom cluster should improve together rather than only one isolated symptom changing.

Expected early responses include:

• Reduced palpitations and upward rushing

• Reduced dizziness on standing

• Reduced epigastric or upper-abdominal discomfort

• Faster recovery after caffeine, stress, heat, or sweating

• Reduced simultaneous fluctuation of the symptom cluster

An important reassessment example is:

“The palpitations improved, but the epigastric discomfort and dizziness did not change.”

In this situation, the overall formula hypothesis should be reconsidered.

Ling Gui Zhu Gan Tang is not intended to treat three unrelated symptoms independently.

It addresses a linked physiological system.

20. FINAL DEFINITION

Ling Gui Zhu Gan Tang is a formula for a low-reserve, high-reactivity patient in whom fluctuations in fluid state and blood-flow distribution become amplified into compensatory palpitations, upward rushing, and dizziness, while post-intake epigastric sensorimotor instability repeatedly triggers and sustains the same symptom cluster.

21. THE METHOD LEARNED FROM THIS PROCESS

The most important result of this analysis was not the final interpretation of one formula.

It was the method used to reach it.

First, do not calculate a formula by adding together the textbook actions of individual herbs.

Second, identify minimal herb combinations that recur across multiple formulas.

Third, extract the symptoms repeatedly associated with those shared combinations.

Fourth, compare what changes when one herb is added or removed.

Fifth, infer the incremental function of that herb from the newly added or removed findings.

Sixth, establish the classical clinical function before attempting a modern translation.

Seventh, translate the observed clinical function into plausible modern pathophysiology.

Eighth, examine whether modern pharmacology supports, partially supports, contradicts, or fails to explain the hypothesis.

Ninth, never force pharmacology to explain more than the evidence allows.

Tenth, distinguish the patient’s background phenotype from the active pathological state.

Eleventh, define what should improve first if the formula hypothesis is correct.

Twelfth, revise or abandon the hypothesis when the expected linked response does not occur.

22. A MESSAGE TO FUTURE CLINICIANS

Memorizing a formula is easy.

Understanding why the formula was constructed in that particular way requires repeatedly asking:

Why is this herb necessary?

Why this herb rather than another?

What new symptom appears when the herb is added?

What function disappears when it is removed?

What physiological state does the herb combination address?

To what extent does modern pharmacology support this interpretation?

Where does observation end and interpretation begin?

What should improve first when the prescription is correct?

What hypothesis must be abandoned when the expected change does not occur?

The architecture of Ling Gui Zhu Gan Tang should not be treated as a final truth.

It is a provisional model that integrates:

• Classical literature

• Repeated historical clinical observations

• Comparative formula analysis

• Contemporary physiology

• Modern pharmacology

• Clinical observations from YOON CLINIC

Its purpose is to explain the observed clinical reality as coherently as possible with the knowledge currently available.

When a stronger and more explanatory model emerges, this model should be revised or replaced.

Good formula study is not the memorization of prescriptions.

It is the discipline of continuing to ask why particular herbs must exist together.