Introduction:

Sini San was first recorded in Chapter 318 of Treatise on Febrile Diseases: “For Shaoyin disease with cold extremities, accompanied by thirst, palpitations, dysuria, abdominal pain, or tenesmus with diarrhea, Sini San governs.” There has long been debate regarding which meridian disorder corresponds to the Sini San syndrome. Cheng Wuji, Qian Tianlai, You Zaijing and Chen Xiuyuan subscribed to the theory of Shaoyin disease, while Wu Qian held the view of concurrent Shaoyang and Jueyin disease. Other scholars advocated theories of Taiyin disease or Shaoyang disease. No consensus has been reached to date; nevertheless, this has not hindered its clinical application. Sini San embodies profound therapeutic principles in herb composition. Remarkable curative effects can be achieved through syndrome differentiation, modification and combined use with other formulas in clinical practice. This paper introduces Professor Tang’s proven cases^[1-2] and follows Wu’s theory of concurrent Shaoyang and Jueyin disease, aiming to facilitate better understanding and application of this formula. Any oversights are open to correction by peers.

Pathogenesis Analysis of Sini San

Views of Various Scholars

The Sini San syndrome is characterized by sini, meaning cold extremities. There are roughly four viewpoints regarding the nature of cold extremities in this syndrome: ① Cold reversal due to deficient and cold yang. The original text begins with “Shaoyin disease”, which should be accompanied by the signs of Shaoyin disease such as “fine and faint pulse, and desire only to sleep”. When Shaoyin yang qi declines, fire fails to generate earth and spleen yang loses its warming function, resulting in abdominal pain and tenesmus with diarrhea. The spleen governs the four limbs; when spleen and kidney yang decline, yang qi cannot diffuse to the extremities, thereby causing cold reversal of the limbs. This viewpoint was held by Shu Chiyuan and Qian Tianlai. ② Heat reversal caused by pathogenic heat transmitting into yin. Cold pathogenic factors in Treatise on Febrile Diseases transform into heat after transmission through the three yang meridians and penetrate deeply into Shaoyin. Internal stagnation and disturbance of pathogenic heat may also lead to abdominal pain and tenesmus with diarrhea. Disharmony between meridian and fu qi traps heat internally, which cannot reach the exterior, hence cold limbs appear. As stated in Annotations on Treatise on Febrile Diseases, “Sini San disperses heat that has transmitted into yin”. Fang Youzhi, Zhang Nan, Wang Zijie and other scholars shared this opinion. ③ Stagnation reversal due to earth qi binding and stomach qi discomfort. The stomach is the sea of the five zang-organs, six fu-organs and twelve meridians. Stagnation of stomach earth qi leads to congestion and disorder of qi and blood, which cannot be normally distributed to the extremities, manifesting as cold limbs. This theory was advocated by Zhang Zhicong, Huang Yuanyu and others. ④ Qi reversal resulting from internal stagnation of yang qi failing to diffuse. The four limbs are the root of all yang and require constant warming by yang qi. Yang qi in the human body values unobstructed circulation. Slight stagnation and dysfunction of the Shaoyin yin pivot prevent yang qi from diffusing to warm the extremities and thus cold reversal occurs. As Wu Qian commented: “Here only cold extremities are present without other cold or heat signs. There is neither cold to be warmed nor heat to be purged; only yang needs to be unblocked, so Sini San is used as the main formula.” Most ancient and modern physicians endorse this theory.

​​​​​​​The Author’s Perspectives

It is stated in Suwen·On Prohibitions of Acupuncture: “The liver originates on the left; the lung resides on the right; the heart spreads to the exterior; the kidney governs the interior; the spleen acts as the messenger, and the stomach serves as the market.” The human body takes the five zang-organs as its foundation. The qi of liver wood ascends on the left, the qi of lung metal descends on the right, the qi of heart fire disperses to the exterior, and the qi of kidney water converges in the interior. The spleen ascends while the stomach descends, and the middle earth pivot mediates the central qi. Nevertheless, the qi movement of zang-fu organs cannot function in isolation and requires coordination. Among them, the heart pertains to fire and is the greater yang within yin; the kidney pertains to water and is the greater yin within yin. Heart fire descends to the kidney and transforms into the genuine yang within the kidney, keeping kidney water from being cold; kidney water ascends to the heart and transforms into the yin blood within the heart, preventing excessive blazing of heart fire. Heart fire generates spleen earth, and kidney water generates liver wood. Spleen earth, the extreme yin within yin, governs ascent; liver wood, the lesser yang within yin, also governs ascent. Liver wood and spleen earth constitute the driving force and pathway for kidney water to ascend and interact with heart fire. As written in Notes on Medical Essays: “The spleen is the pathway for ascent and descent; the liver is the root initiating ascent and descent.” The joint ascent of the liver and spleen enables the cold water of the kidney to reach the monarch heart. Correspondingly, the joint descent of the lung and stomach allows the yang fire of the heart to descend to kidney water. Such coordination accomplishes the interaction between heart and kidney and the harmony of yin and yang.

The Sini San syndrome arises when liver qi fails to ascend and the spleen pathway becomes obstructed. Kidney water cannot ascend to nourish heart fire and transform into yin blood, leading to insufficiency of heart yin. The body substance fails to support functional activities, and yang cannot diffuse outward to the extremities, resulting in cold limbs as the primary manifestation. The disorder affects the unsmooth qi movement of the heart and kidney of Shaoyin, which explains why the original text of Treatise on Febrile Diseases labels it “Shaoyin disease”. It is reasonable that this syndrome is recorded in the Shaoyin chapter. The accompanying symptoms “or cough, or palpitations, or dysuria, or abdominal pain, or tenesmus with diarrhea” in the text all stem from failing dispersion of liver qi, stagnation of the spleen earth pathway, and disordered qi movement. Clinically, disorders caused by inhibited liver and spleen are quite common. Zhongjing only listed five optional symptoms to illustrate the broad applicability of this formula. Although the illness involves the heart and kidney, cases centered on pathological changes of the heart and kidney are relatively rare. The heart and kidney themselves remain intact; only the pathway for heart-kidney interaction is blocked. Therefore, disorders originating from the liver and spleen are most frequently encountered.

Zhongjing clearly stated in the preface of Treatise on Febrile Diseases that he “compiled and adopted contents from Suwen and Nine Volumes … and diagnosed diseases by analyzing pulses and differentiating syndromes”. Therefore, the analysis of the Sini San syndrome should be traced back to Suwen and Nine Volumes. Combined with the discussion above, the author holds that the Sini San syndrome is indeed a Shaoyin disease and naturally belongs to the Shaoyin chapter. It was not placed in the Shaoyin chapter merely for Zhongjing to distinguish its “cold extremities” from those of the Sini Tang syndrome. The cold extremities in the Sini San syndrome result from reversal due to Shaoyin qi stagnation, which differs drastically from the cold extremities of the Sini Tang syndrome caused by depletion and collapse of yang qi, leaving little necessity for comparison. Physicians of successive generations, as well as modern experts and scholars studying Treatise on Febrile Diseases, have put forward their own understandings of the etiology and pathogenesis of the Sini San syndrome. Most of them subscribe to the theory of concurrent Shaoyang and Jueyin disease, which holds that pathogenic factors transmit from the three yang meridians to Jueyin to form a combined disease, and Sini San is formulated precisely for this concurrent Shaoyang-Jueyin disease.

​​​​​​​Tongue and Pulse Manifestations of Sini San Syndrome

  Combined with the above viewpoints of various scholars, the most common pulse manifestation in the Sini San syndrome is the string-like pulse, which signifies stagnation and obstruction. There are numerous causes for such stagnation. When stagnation arises from accumulated phlegm-dampness and fluid retention, a string-slippery pulse can be observed; when it is caused by static blood binding and stagnation, string-rough or string-thin pulses may appear; when stagnant fire is constrained and latent, string-rapid, string-stiff, deep-string and agitated pulses can be detected. The pulse manifestations are most prominent at the two guan positions. Regardless of the pulse type, the force upon deep palpation is not markedly weak. As for the tongue, the tongue body is usually firm, aged and dry with a slightly dark or faintly purplish hue. The coating is thin, either thin white or thin yellow, often scanty in fluid and unmoistened, or greasy.

2 Formula Analysis of Sini San

Sini San consists of merely four herbs, yet it features an ingenious formula composition and remarkable compatibility. It contains four fundamental formula combinations: Chaihu and Gancao; Shaoyao and Gancao; Zhishi and Shaoyao; and Chaihu, Zhishi together with Shaoyao. The skillful integration of these four basic formula combinations lays the foundation for the potent therapeutic effects of Sini San^[3].

2.1 Chaihu and Gancao

Chaihu and Gancao constitute the embryonic form of Xiaochaihu Tang. Zou Shu stated: “Xiaochaihu Tang contains seven herbs. Five of them are subject to modification, while only Chaihu and Gancao cannot be altered. They stabilize the interior and resist external pathogens, and neither can be omitted.” (Comprehensive Commentary on the Divine Husbandman’s Materia Medica). This herb pair represents the most critical compatibility in Sini San. In the formula, Chaihu is bitter and neutral in nature, endowed with Shaoyang qi. It enters the liver, acting directly to follow its innate property of spring ascent and dispersion. It can dispel pathogenic factors, ascend and diffuse clear qi, lift collapsed liver qi to ascend from the left, and guide clear qi to travel along yang pathways. Moreover, it carries the qi of Taiyin earth, enters the spleen and stomach, resolves bound qi in the intestines and stomach, promotes free flow of qi and blood, and unblocks stagnation. In summary, Chaihu soothes and frees liver wood, disperses stagnant pathogens and ascends clear yang, unblocks the spleen and stomach, and eliminates the old to generate the new.

2.2 Shaoyao and Gancao

The combination of Shaoyao and Gancao generates yin through sour-sweet interaction, promoting the production of fluid and blood, lubricating and descending stagnation, and unblocking the pathways. Sour, bitter and neutral in nature, Shaoyao bears luxuriant large flowers and is abundant in spring qi. It can restrain liver qi and serves as an excellent medicinal herb for nourishing the liver. Entering the blood aspect of liver wood, it “restrains body fluids and protects nutrient blood, constrains liver qi and discharges pathogenic heat” (Insights into the Original Meaning of the Materia Medica). As body fluids, blood and yin qi are conserved and nourished, stagnation can no longer attach and linger. By virtue of its bitter property for downward discharge, it can accordingly attack and descend floating and diffused stagnation. Paired with Gancao, which tonifies qi and blood, liver blood is well nourished, and the inherent functions of ascent and dispersion of the liver can be fully exerted. It can also “enter the spleen to break qi stagnation within the blood” (Reflections on Materia Medica). Once yin stagnation in the spleen is resolved, the liver and spleen become unobstructed, yang qi can diffuse freely, and yin and yang are harmonized.

2.3 Zhishi and Shaoyao

The pairing of Zhishi and Shaoyao in Sini San inherits the effect of Zhishi Shaoyao San to resolve stagnation of phlegm, qi and blood. Bitter and cold in nature, Zhishi acts forcefully and swiftly, possessing the property of “dredging, discharging and breaking hard masses” (Supplement to the Extended Meaning of Materia Medica). Round in shape and aromatic, it is an agent for diffusing the spleen and stomach, thus unblocking the stomach collaterals. Insights into the Original Meaning of the Materia Medica summarizes its functions: “It enters the blood aspect of the liver and spleen, promotes digestion, purges phlegm, lubricates orifices and breaks qi stagnation.” Combined with Shaoyao, which constrains liver fluid and restrains liver qi, it further assists Zhishi in resolving yin stagnation of the liver and spleen. Together, they achieve the effects of eliminating phlegm binding and blood stagnation, and diffusing qi movement.

2.4 Chaihu, Zhishi and Shaoyao

In this formula, Zhishi combined with Chaihu exerts the effects through bitter and acrid properties, ascending clear qi and descending turbid pathogens, smoothing the liver and spleen, and balancing yin and yang. The ascending action guides clear qi upward to the upper jiao, heart, lung and head; the descending action directs qi downward to the large and small intestines, unblocking fu-organs, resolving stagnation and dissipating masses. Further supplemented with Shaoyao, it assists the ascending, descending and unblocking actions of the two herbs, while preventing injury to healthy qi and consumption of qi.

In terms of qi aspect: Zhishi breaks stagnation and descends qi; Chaihu disperses and ascends qi; Shaoyao restrains misplaced qi.In terms of blood aspect: Chaihu regulates qi to activate blood circulation; Zhishi breaks static binding; Shaoyao harmonizes nutrient blood and discharges blood stagnation.In terms of exterior and interior: Chaihu soothes and promotes outward diffusion; Zhishi eliminates stagnation and conducts downward movement internally; Shaoyao dredges the meridians and collaterals.In terms of yin and yang: Chaihu and Gancao activate yang; Zhishi and Shaoyao act on yin. Yang governs ascent while yin governs descent. Proper coordination of ascent and descent ensures unobstructed qi movement and qi circulation throughout the whole body.

3. Representative Case Studies

A female patient, aged 35, presented for the first visit on May 15, 2012. Gastroscopy performed in another hospital in March 2012 revealed chronic superficial gastritis (CSG) with erosion, duodenal bulb erosion and positive Helicobacter pylori (HP). The patient had received triple antimicrobial therapy. Current symptoms: normal appetite, epigastric fullness and distension after meals, ineffective belching, no acid regurgitation, epigastric distending pain, one bowel movement daily. The tongue was slightly enlarged with thin coating; the pulse was thin and slippery, accompanied by bitter taste in the mouth. Professor Tang prescribed the following formula: Codonopsis Radix 15 g, stir-fried Atractylodis Macrocephalae Radix 15 g, processed Pinelliae Rhizoma 9 g, Coptidis Rhizoma 6 g, Evodiae Fructus 2 g, Sepiae Endoconcha 30 g, Perillae Fructus and Perillae Folium 12 g, Aurantii Fructus Immaturus 15 g, Amomi Fructus 9 g (decocted later), Amomi Rotundus Fructus 6 g (decocted later), Salviae Miltiorrhizae Radix et Rhizoma 24 g, Talcum 10 g (wrapped for decoction), Corydalis Rhizoma 12 g, Toosendan Fructus 9 g, roasted Glycyrrhizae Radix et Rhizoma 6 g.

Second visit: The patient presented with signs of “stomach fire” involving ears and nose, dry mouth, dry nose, facial acne, cold sensation, aversion to cold of lower extremities, dry and itchy ear canals, epigastric burning, occasional acid regurgitation, and one bowel movement per day. The tongue had tooth marks on the edge with thin yellow coating; the pulse was thin and slippery. Professor Tang prescribed: Chaihu 10 g, Radix Paeoniae Rubra and Radix Paeoniae Alba 15 g each, Aurantii Fructus Immaturus 15 g, Prunellae Spica 15 g, Gentianae Radix et Rhizoma 9 g, Moutan Cortex 12 g, Gardeniae Fructus 12 g, Scutellariae Radix 12 g, Asari Radix et Rhizoma 3 g, Angelicae Sinensis Radix 15 g, raw Astragali Radix 18 g, Cinnamomi Ramulus 6 g, Linderae Radix 30 g, Corydalis Rhizoma 12 g, Plantaginis Semen 10 g (wrapped for decoction), roasted Glycyrrhizae Radix et Rhizoma 6 g.

Third visit: Symptoms of the lower extremities nearly resolved. The patient experienced burning sensation in the middle and upper epigastrium, acid regurgitation occurring both on an empty stomach and after meals, and facial acne. The tongue was pale-red with tooth marks on the edge and thin coating; the pulse was thin and string-like. Stool was unformed, and there was a hot sensation during urination and defecation. Professor Tang prescribed: Chaihu 10 g, Radix Paeoniae Rubra and Radix Paeoniae Alba 15 g each, Aurantii Fructus 12 g, roasted Glycyrrhizae Radix et Rhizoma 6 g, Coptidis Rhizoma 6 g, processed Zingiberis Rhizoma 4 g, Sepiae Endoconcha 30 g, stir-fried Atractylodis Macrocephalae Radix 20 g, Poria Cocos 15 g, Talcum 10 g, Phragmitis Rhizoma 30 g, roasted Glycyrrhizae Radix et Rhizoma 6 g, Codonopsis Radix 15 g, processed Pinelliae Rhizoma 9 g.

Fourth visit: The patient reported dark clotted menstrual blood, abdominal pain, and mammary gland hyperplasia. She felt hungry easily with hunger pangs, occasional acid regurgitation and rare belching. Bowel movements occurred once or every two days, with poor defecation and poorly formed stool. Menstruation had just ceased. The tongue was slightly enlarged with thin coating; the pulse was deep and slippery. Professor Tang prescribed: Chaihu 10 g, Radix Paeoniae Alba 15 g, Angelicae Sinensis Radix 12 g, Aurantii Fructus 15 g, Gentianae Radix et Rhizoma 6 g, Coptidis Rhizoma 6 g, Evodiae Fructus 2 g, Chuanxiong Rhizoma 12 g, Citri Folium 15 g, Citri Semen 15 g, Amomi Fructus 6 g (decocted later), Corydalis Rhizoma 12 g, Toosendan Fructus 9 g, roasted Glycyrrhizae Radix et Rhizoma 6 g, Taraxaci Herba 20 g.

Fifth visit: Facial acne was alleviated. Acid regurgitation and heartburn persisted, accompanied by foreign body sensation in the throat and distension below the left hypochondrium. The tongue coating was thin; the pulse was thin and string-like. Professor Tang modified the previous formula by adding raw Astragali Radix 24 g, Litchi Semen 30 g, and Linderae Radix 30 g.

Subsequently, all symptoms were relieved; no further follow‑up was conducted.

Comments

This patient appeared to suffer from inability to tonify due to deficiency, yet she was by no means of a deficient constitution. Slight tonification would trigger upward flaming of fire, which referred to upward surging of yin fire from the liver and kidney. It would be erroneous to simply clear and purge stomach fire. The therapeutic principle was to clear liver fire and calm counterflow qi. Professor Tang initially attempted spleen-regulating therapy, which yielded no effect, so he promptly shifted to methods for clearing and pacifying the liver. In addition, the patient manifested cold reversal of lower extremities; mild acrid-warm medicinal herbs were added as counter-adjuvants. Later, considering her facial acne and special menstrual phase, herbs for purging the liver or unblocking collaterals were supplemented.

Erchen Tang was adopted in this case because the spleen failed to perform transportation and transformation. The refined substances from water and grains could not be transported and distributed, accumulating to form dampness and then phlegm. Phlegm-dampness is slippery and mobile, ascending and descending along with qi and reaching everywhere in the body. Once it obstructs the pathway between the liver and spleen, binding stagnation of liver wood and spleen earth occurs, leading to disordered qi movement. Therefore, Sini San was used to soothe liver wood and unblock spleen earth, combined with Erchen Tang to dry accumulated dampness and resolve bound phlegm, remove phlegm-damp obstruction, and restore unobstructed qi circulation throughout the body.

As stated in Standards for Diagnosis and Treatment: “Those who excel at treating phlegm do not treat phlegm directly but regulate qi. When qi flows smoothly, body fluids of the whole body follow qi to move harmoniously.” Sini San regulates stagnation and governs qi movement, while Erchen Tang smooths qi and treats phlegm. The combined therapy addresses both phlegm and qi, resolves stagnation and harmonizes the liver and spleen.

As early as in Case Records as a Guide to Clinical Practice, Ye Tianshi put forward the theory that the liver possesses yin as its substance and yang as its function. As discussed in Case Records as a Guide to Clinical Practice · Liver Wind^[4]: “The liver … entirely relies on kidney water to nourish it, blood to moisten it … and earth qi to foster it.” The liver receives refined substances of water and grain transformed by the spleen, which combine with essence stored in the kidney to generate liver qi, thereby exerting the dispersing and discharging function and regulating qi movement of the whole body.

In Sini San, Chaihu acts as the monarch herb, conforming to the nature of the liver and promoting its functional activities. As the minister herb, Baishao restrains the liver’s propensity and constrains liver function. One governs yang and the other yin; one acts on qi and the other on blood. Together they harmonize liver qi and liver yin. Zhishi breaks liver qi stagnation with a fierce nature; clinically, Aurantii Fructus (zhiqiao) is often used instead for its milder property to prevent impairment of liver function. Hence Professor Tang prefers Zhiqiao rather than Zhishi. When heat is generated from disordered liver function, herbs such as Chishao, Moutan Cortex and Gentianae Radix et Rhizoma may be added appropriately.

4 Conclusion

Sini San has long been regarded as a fundamental formula for “harmonizing the liver and spleen”. In its composition, Chaihu, Shaoyao, Zhishi and Gancao each perform their respective functions and interact with one another, exerting the effects of soothing liver qi, smoothing qi movement, invigorating the spleen and harmonizing the middle jiao. Annotated Treatise on Febrile Diseases states: “When the disease progresses to the Shaoyin stage, pathogenic heat gradually deepens, thereby causing coldness of the four limbs… Sini San is used to dispel heat that has transmitted into the yin meridians.” Exposition on Febrile Diseases notes: “Sini refers to cold and cool extremities. …The formula consists of Chaihu, Zhishi, Shaoyao and Gancao. All four herbs are cold in nature and specifically treat the sini disorder, which indicates that sini here is not a cold-deficiency syndrome.” Cheng Wuji held that the cold extremities treated by Sini San arise from yang qi being constrained internally so that the extremities cannot be warmed, rather than cold limbs caused by yang depletion and yin reversal.

Wu Qian of the Qing dynasty interpreted the “harmonizing and resolving” effect of Sini San, pointing out that Sini San treats heat reversal syndrome due to internal constraint of yang qi and classified Sini San under the category of Shaoyang disease. As recorded in Golden Mirror of Medicine: “The formula is named Sini San. Both Sini San and Sini Tang treat cold hands and feet. However, Sini Tang treats cold reversal caused by yin pathogens, while this formula treats heat reversal caused by yang pathogens. Heat reversal results from combined disease when pathogens transmit from the three yang meridians to Jueyin… This case pertains to Shaoyang and Jueyin…”

It is not difficult to distinguish: Zhongjing placed Sini San in the Shaoyin chapter to teach practitioners to differentiate yin reversal from yang reversal and avoid misleading later generations. Therefore, Sini San governs yang reversal. Yang reversal originates from stagnation and obstruction of qi movement, and heat develops after prolonged stagnation. This view has been advocated by most physicians from ancient times to the present.

Traditional Chinese medicine holds that yang qi within the human body values unceasing circulation. Even slight stagnation will impair the pivot function of Shaoyin, preventing yang qi from freely diffusing and warming the four extremities and consequently resulting in reversal. As Wu Qian stated: “Here there is only cold extremities without other cold or heat symptoms. It means there exists neither cold requiring warming nor heat requiring purgation. Only freeing and unblocking yang qi is appropriate; hence Sini San is indicated for this condition.”

In the clinical diagnosis and treatment of chronic gastritis in traditional Chinese medicine, practitioners may focus on the spleen and stomach and may also treat from the liver perspective. Both Professor Dong’s unblocking and descending theory and Professor Tang’s modified Sini San share a common pathogenic mechanism, namely impaired liver dispersion, obstructed spleen transportation, and constrained yang qi. In TCM clinical practice, hunger pangs are a sign of stagnant heat transforming into fire. When pathogenic fire accumulates and hides internally, it readily consumes body fluids and qi. It is self-evident that fire injures fluids; consumption of qi by pathogenic fire is explained by the classic tenet that “excessive fire consumes qi”. When body fluids are scorched, they tend to condense into phlegm. Impaired healthy qi slows qi movement, resulting in obstructed spleen pathways and failed ascent of liver qi. Fundamentally, the disorder arises from constrained and blocked heat. Professor Tang added Gentianae Radix et Rhizoma and Gardeniae Fructus to strengthen the ascending and descending actions and disperse pathogenic heat at both the exterior and interior. Thereby, stagnant heat is released and dispersed, phlegm is not generated, and qi is not consumed. Given the patient’s stagnant heat and qi binding, Litchi Semen and Taraxaci Herba were supplemented to promote qi movement and dissipate heat. Once qi and body fluids circulate smoothly, spleen-stomach qi recovers spontaneously.

The spleen prefers unobstructed movement, the stomach depends on descending for harmony, and the liver relies on free dispersion for smooth function. For unblocking and descending therapy, dispersion is the priority. Clinically, the reversal of Sini syndrome can be resolved by descending to attain harmony and unblocking to restore smooth flow, which yields remarkable efficacy in clinical application. The Sini pattern refers to counterflow of qi and stagnation of blood. Chaihu conforms to the innate nature of the liver, regulates liver qi, and softens the liver’s functional activity. As stated in Random Notes on Medical Reading^[5]: “The spleen is the pathway for ascent and descent; the liver is the origin where ascent and descent initiate.”

This monograph differentiates ascent‑descent from exit‑entry. Ascent and descent represent the circulating passages of the “interior qi” within the human body. Exit and entry denote the passages for communication between the body’s “interior qi” and external qi. “Interior qi” refers to “body qi”, namely the qi movement of the whole body, together with various qi transformation and functional manifestations generated during qi circulation throughout the body. “External qi” means atmospheric air, the clear qi from nature. This illustrates that ascent‑descent refers to the exchange of qi movement among internal zang‑fu organs.

The liver and spleen govern ascent jointly: cold water from the kidney ascends to nourish the heart. Correspondingly, the lung and stomach govern descent jointly: yang fire from the heart descends to the kidney water. Such coordination fulfills the interaction between heart and kidney and the harmony of yin and yang. The Sini San syndrome manifests when liver qi fails to ascend, the spleen pathway becomes obstructed, kidney water cannot ascend to nourish heart fire and transform into yin blood. Insufficiency of heart yin renders the substance unable to support function, and yang fails to diffuse outward to the four extremities.

Sini San is indeed a time‑honored effective formula for harmonizing the liver and spleen and unblocking stagnant qi in clinical practice.      

Therefore, Professor Tang favors Sini San and its modified prescriptions for the treatment of gastroesophageal reflux disease, chronic gastritis ^[6-10] and other disorders. He flexibly modifies and combines formulas according to clinical presentations. The author had the privilege of accompanying Professor Tang during consultations and gained an in‑depth understanding of the formula’s syndrome pattern and the original design intention of this prescription and hereby shares these insights with peers.

Conflict of Interest statement: All authors declare that there are no conflicts of interest.