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Xiaoming Cheng
Abstract: The Eight Principle diagnostic features are Exterior-Interior, Cold-Heat, Deficient-Excess, and Yin-Yang. These methods of differential diagnosis are used to determine the nature and location of pathological changes. The conflict between the body, the Vital Essence, and the pathogens are evaluated in terms of these Eight Principles. This determination is based on a comprehensive analysis of the clinical evidence obtained by inspection, auscultation, olfaction, interrogation, quality of pulse and palpation.
Differential Diagnosis of Interior or Exterior Syndrome
This method of differential diagnosis is used to determine the location of the pathogen and the probability for the development of a disease (i.e. the potential for transformation).
The main syndromes are listed below.
Exterior Syndrome
This refers to a syndrome caused by an attack of the superficial or Exterior of the body by the Six Pathogenic Influences through the skin, hair, mouth or nose. It is sudden in onset, superficial (limited to the Exterior), mild in nature, and short in duration without affecting the function of Zang Fu in most cases.
Interior Syndrome
In contrast to the Exterior syndrome, the Interior syndrome is characterized by pathological changes of the internal organs. The Interior syndrome may be caused by pathogenic influences, which either enter from outside of the body or transfer into the interior, or by their direct invasion of the Zang Fu. The Interior syndrome may also be caused by some “internal influences”, such as emotional upset, improper diet or psychological stress, which directly affect the function of the Zang Fu.
Invasion from the Exterior to the Interior
This refers to the invasion of pathogens from superficial aspects of the body to the deep, or the replacement of an Exterior syndrome by an Interior one.A patient with an Exterior syndrome may have such symptoms as fever and aversion to cold, and the tongue may be normal with a white thin coating and a floating pulse. If the sensation of aversion to cold is replaced by aversion to heat, then new symptoms may appear. These symptoms include thirst, scanty dark urine, redness of the tongue with yellowish coating and rapid pulse, indicating that the disease has manifested itself by an Interior Heat syndrome due to an invasion of pathogenic agents from the superficial part of the body to the deep.
Invasion from the Interior to the Exterior of the body
This refers to the conditions in which the pathogenic factors are brought out from the Interior to the body’s Exterior. For example, in the case of an Interior syndrome due to Interior Heat, at first there is the appearance of restlessness, shortness of breath, cough and chest stuffiness.Then there is progression to fever and sweating, the restlessness subsides or a rash develops. These symptoms indicate that the pathogenic agent has been brought out to the surface and the Interior syndrome has subsided. This usually results from proper and prompt treatment and appropriate nursing, which helps to build up the body’s resistance. The transmission of pathogens from the Interior to the Exterior is indicative of the convalescence of a disease in which the pathogens have been expelled, and the condition of the illness has abated.
Mixed Syndrome of Exterior and Interior
This refers to the simultaneous appearance of features from both the Exterior syndrome and the Interior syndrome in a patient. Evidence of both Exterior and Interior syndromes appears in the initial stage of an illness. For example, when in late summer or in early autumn, there may appear symptoms characteristic of Exterior syndrome, such as fever, aversion to cold, headache, and general aching sensation on the body. In addition, symptoms characteristic of Interior syndrome, such as epigastria stuffiness, anorexia, diarrhea, thick whitish coating of the tongue, etc. may also be present. This is due to an invasion by External pathogenic Cold and Internal pathogenic Dampness.
Differential Diagnosis of Cold and Heat Syndromes
This refers to the method of differentiating the nature of a disease. It is identical with the differentiation of Excess and Deficiency of Yin and Yang, because Cold and Heat are the manifestations of Excess and Deficiency of Yin and Yang in the body.
The main syndromes are:
Cold Syndrome
This syndrome can be caused by an invasion of a Cold Pathogenic Influence, also known as Excessive Cold. Another form of Cold syndrome is Interior Deficiency Cold, in which the client always feels cold internally. This is due to insufficiency of Yang and excess of Yin. Clinical manifestations of a Cold syndrome are: aversion to cold, seeking or desire for warmth, no thirst, pale complexion, huddling up when cold, copious clear urine, loose stools, pale tongue with whitish coating, and a tense or slow pulse.
Heat Syndrome
This is a syndrome caused by invasion of pathogenic Heat or hyperactivity of the body due to a Deficiency of Yin and Excess of Yang. Clinical manifestations are fever, aversion to heat and preference for cold, thirst with a preference for cold drinks, flushed face, congested eyes, fidgeting, scanty dark urine, constipation, reddened tongue with dry brownish coating and a rapid pulse.
Simultaneous Occurrence of Cold and Heat Syndromes
This means that a Cold syndrome is intertwined with a Heat syndrome in the same patient.This may appear as an Organ disorder, characterized by a Heat syndrome in the upper part with a Cold syndrome in the lower part of the body, or it may appear in the organs themselves.
In the case of simultaneous occurrence of an Exterior and Interior syndrome, it is marked by a Heat syndrome in the Exterior with Cold syndrome in the Interior, or vice versa.
Transformation of a Cold Syndrome and a Heat Syndrome
This refers to a change in the nature of a disease. There is a transfer from a Cold syndrome to a Heat syndrome. For example, when a Cold Pathogenic Influence invades the body, we can see such symptoms as fever, aversion to cold, no sweat, headache, general aching, thin white coating of the tongue, tight floating pulse, etc. Later, owing to further development of the pathological changes, the aversion to cold disappears but the fever does not abate, and an aversion to heat rather than cold occurs. Moreover, other symptoms progressively appear such as irritability, thirst and yellowish coating of the tongue, indicating that the Exterior Cold syndrome has transformed into an Interior Heat syndrome. On the other hand, a disease can initially manifest as a Heat syndrome followed later by a Cold syndrome. This transformation of a Heat syndrome into a Cold syndrome is seen in the case of a patient with high fever due to delayed treatment or misdiagnosis. The patient may be overcome by the pathogenic factor, which damages the Vital Qi and suddenly develops such symptoms as cold limbs, profuse cold sweat, restlessness, and a faint indistinct pulse. This is also called collapse of Yang.
Heat Syndrome with Pseudo-Cold Symptoms
In this syndrome, the disease has a Heat syndrome nature but also presents with some Cold symptoms, such as cold limbs, deep pulse, etc. It is different from a Cold syndrome in that the patient’s body is warm in spite of cold limbs, and has an aversion to heat instead of cold, and his pulse is deep, but also rapid and forceful. The patient may also have the following symptoms: excessive thirst, preference for cold drinks, dry throat, foul breath, delirium, scanty dark urine, dry stool or dysentery of the Heat type with rectal tenesmus, and a dark reddish tongue with a dry yellowish coating. In this case, the cold limbs and deep pulse are considered “false appearances,” because the Interior Heat is the essence of the disease. This condition is attributable to Excessive Heat inside the body, which keeps Yin superficial. This is what is known as “ Yin kept Externally by Excessive Yang in the Interior”.
Cold Syndrome with Pseudo-Heat Symptoms
In this case, the disease is Cold in nature, but exhibits some Heat symptoms, such as fever, flushed face, thirst, and a large pulse. It differs from a Heat syndrome in that the patient runs a fever, but has a desire for being covered up, feels thirsty, but prefers hot drinks, and the pulse is large but weak. There can be symptoms of a Cold nature observed, such as cold limbs, clear urine, loose stool, and pink tongue with a whitish coating. This syndrome’s cause is an Excessive Yin Cold inside the body, which keeps the Yang External. This is what is called “Yang kept Externally by Excessive Yin in the Interior”.
Overall, the differential diagnosis of cold and heat syndromes constitutes one of the fundamental aspects of Traditional Chinese Medicine (TCM) diagnosis and treatment. Continuing, here are further details on related aspects:
Concurrence of Internal and External Diseases: This refers to a situation where a patient exhibits characteristics of both an internal injury (or internal disease) and an externally contracted disease (or external disease).This might manifest as a heat syndrome in the upper body as per external disease and a cold syndrome in the lower body as per internal injury, or simultaneously in different parts of an organ.
Transformation between Cold and Heat Syndromes: This denotes a change like illness, wherein a cold syndrome might transform into a heat syndrome, and vice versa. Such transformation often accompanies the development of pathological changes, with symptoms gradually altering. In TCM diagnosis and treatment, therapeutic approaches are adjusted according to these changes.
False Cold Symptoms Accompanying Heat Syndrome: I In this scenario, the disease exhibits the characteristics of heat syndrome but also presents some cold symptoms. n this state, the coldness in the limbs and a deep, sunken pulse are considered “false manifestations” because the actual nature of the disease lies in excessive internal heat.
False Heat Symptoms Accompanying Cold Syndrome: In this scenario, the nature of the disease is a cold syndrome but simultaneously presents some heat symptoms. In this state, fever and other heat symptoms are considered “false manifestations” because the actual nature of the disease lies in an excessive yin-cold internally.
Differentiating these cold and heat syndromes aids TCM practitioners in accurately understanding the nature and location of the pathology, thus allowing for the creation of personalized treatment plans. It is important to emphasize that TCM diagnosis and treatment is a comprehensive medical science that not only considers the etiology and pathogenesis of the disease but also considers individual differences, environmental factors, and a principle that integrates prevention and treatment.
Differential Diagnosis of Deficiency and Excess Syndrome
This is a method used to determine the strength of the Vital Qi of the body and the virulence of pathogenic factors.
Deficiency Syndrome
This syndrome manifests by a Deficiency of Vital Qi.
An individual may be born with a Deficiency of Vital Qi. More commonly a Deficiency of Vital Qi is due to a lack of proper living, excess, or imbalance in one’s life. For example, improper diet may lead to weakness of the body’s constitution; emotional upset may impair the Qi and Blood of the Zang Fu; sexual indulgence may consume the Kidney Qi; and prolonged illness may impair the Vital Qi.All these factors may result in various Deficiency syndromes, which include insufficiency and impairment of Yin, Yang, Qi, Blood, Essence of life, body fluid, and the Zang Fu.Clinical manifestations are: pale or yellowish complexion, restlessness, emaciation, fatigue and weakness, disinclination to talk, palpitation, shortness of breath, lassitude in loins and knees, spontaneous perspiration, night sweat, incontinence of stool and urine, pain relieved by pressing, pink tongue with little or not coating, and feeble or weak pulse.
Excess Syndrome
This syndrome is manifested by exuberant pathogens. It may result from an excess of pathogens with the Vital Qi not in decline; this condition leads to an intense struggle within the body between these two forces. The main manifestations of Excess syndrome are: strong physical constitution, high fever, agitation, loud voice, abdominal distension, pain and tenderness, constipation, hot burning sensation in urine, rough pale tongue with thick and greasy coating, replete and forceful pulse.
Deficiency Syndrome complicated with Excess Syndrome
This refers to the simultaneous occurrence of a Deficiency syndrome and an Excess syndrome in the same patient at the same time. For example, if a Deficiency syndrome is dominant, and is complicated with Excess symptoms, a patient may exhibit Blood-Deficient insomnia, with a headache in the back of the head, which is caused by a stiff neck.
In the case where an Excess syndrome is predominant, but accompanied by Deficiency symptoms, a patient may suffer from a Cold Pathogenic Influence, with headache, body aches and cough, meanwhile also displaying symptoms of Spleen Deficiency, such as feeling tired, loose stools and bloated abdomen.
Transformation of Excess Syndrome to Deficiency Sndrome
An Excess syndrome characterizes the disease in its initial stage. However, due to delayed treatment or misdiagnosis, it evolves into a Deficiency syndrome as a result of a decline of the pathogen and the impairment of Vital Qi due to the protracted course of disease. For example, a patient develops acute diarrhea and is not properly treated or is misdiagnosed. After a few months, it transfers to a Deficiency syndrome, i.e. chronic diarrhea. This is what is known as the transformation of Excess syndrome to Deficiency syndrome.
Transformation of Deficiency Syndrome to Excess Syndrome
In this syndrome a Deficiency syndrome characterizes the disease in its early stage. Due to insufficiency of Vital Qi, substantial pathogens gradually accumulate inside the body and give rise to some Excess symptoms. For example, Qi Deficiency in the elderly may cause exhaustion of body fluid and dryness of the intestine. This may then lead to an Excess syndrome manifested by constipation. This is known as Excess syndrome due to Deficiency syndrome.
Excess Syndrome with Pseudo-deficiency Symptoms
This is a syndrome of Excess type characterized by the accumulation of pathogens, but accompanied by symptoms similar to a Deficiency syndrome. It is also known as “appearance of Deficiency in extreme Excess”. For example, the accumulation of Heat or retention of Phlegm and food in the Stomach and Intestines may lead to blockage of movement of Stomach and Intestinal Qi. This is accompanied with symptoms such as lassitude, chilliness and cold limbs, and slow deep hidden pulse. Upon careful examination, other symptoms may be found such as loud voice, rough breathing, deep and slow or hidden but strong pulse, indicating that accumulation of pathogens in the interior as the real essence of disease, while symptoms resembling a Deficiency syndrome are merely false phenomena.
Deficiency Syndrome with Pseudo-excess Symptoms
This is a syndrome of Deficiency, but accompanied by symptoms similar to an Excess syndrome. It is also called “False Excess symptoms in extreme Deficiency”. For example, dysfunction of Zang Fu in digesting and transporting nutrients due to insufficiency of Qi and Blood may produce symptoms similar to an Excess syndrome, such as abdominal fullness, distension and pain, wiry pulse, etc. However, upon careful examination it may be found that the abdominal distension is slight, not severe. Moreover it is not persistent and can be relieved by pressure, and that the patient’s pulse is wiry and weak indicating that an insufficiency of Qi and Blood of Zang Fu is the real essence of disease. Once again the symptoms similar to an Excess syndrome are but false phenomena.
Complicated Syndromes
Exterior Syndrome of Excess type: This syndrome results in a tight sensation of the skin and muscles due to invasion of the superficies by a Pathogenic Influence. This manifests as dry skin, no sweat, fever, aversion to cold, headache, body aching, stuffy nose, and a tense floating pulse.
Exterior Syndrome of Deficiency type: This syndrome is also called “Disharmony of Ying and Wei Qi.” Its clinical manifestations are spontaneous sweating, fever, aversion to wind, sweating, and a slow floating pulse.
Cold Syndrome of Deficiency type: This syndrome is caused by a Yang Qi deficiency. It is manifested by lassitude, pale complexion, aversion to cold and cold limbs, abdominal pain, which is relieved by warmth and pressure, loose stool, frequent clear urine, shortness of breath and weakness, pale tongue, feeble or deep, slow and weak pulse, etc.
Cold Syndrome of Excess type: This syndrome is due to Excessive Yin-Cold inside the body, and stagnation of Yang Qi. This syndrome results from excessive intake of cold or raw food, or direct invasion of the Interior by a Cold Pathogenic Influence. It manifests as aversion to cold and cold limbs, epigastric chilliness and pain, abdominal pain and tenderness, vomiting of watery fluid, borborygmus, chronic diarrhea, cough with profuse thin and whitish sputum, asthma, whitish slippery coating of the tongue, and slow or tense pulse.
Yin Yang Dialectics
Differential Diagnosis of Yin and Yang is a general guiding principle underlying all Differential Diagnoses by the Eight Principles. The principles of Yin and Yang govern the other six principles. In times when there is no clear pattern for diagnosis, one can simplify their approach to the patient by applying the differential diagnosis of Yin and Yang.
Basic Concepts of Yin and Yang:
Mutual Relationship of Yin and Yang: Yin and Yang are concepts of mutual dependence and restraint. They exist in a relationship where one is relative to the other. The balance of the body relies on the equilibrium of Yin and Yang.
Dynamic Changes of Yin and Yang: Yin and Yang are dynamically changing, not static. The balance between Yin and Yang can vary with factors such as time, season, environment, etc.
Relativity of Yin and Yang: Yin and Yang are relative, meaning one exists in relation to the other. In a specific context, something may manifest as Yin in one aspect and Yang in another.
Mutual Transformation of Yin and Yang: Yin and Yang can transform into each other under certain conditions. This dynamic balance helps maintain stability in both physiological and pathological states.
Application of Differential Diagnosis of Yin and Yang:
No Clear Diagnostic Pattern: When a patient’s symptoms do not clearly align with any specific pattern of the Eight Principles, the differential diagnosis of Yin and Yang can be applied to preliminarily assess the patient’s constitution and pathological characteristics.
Guidance for Holistic Diagnosis: Differential Diagnosis of Yin and Yang aids in guiding the overall diagnostic process. Understanding the balance of Yin and Yang within the patient’s body contributes to a more comprehensive understanding of the disease process.
Individualized Treatment Plans: Differential Diagnosis of Yin and Yang assists in formulating more individualized treatment plans. Adjusting treatment strategies based on the specific imbalance of Yin and Yang in the patient’s body promotes overall balance.
In summary, the Differential Diagnosis of Yin and Yang is fundamental to traditional Chinese medicine diagnostics and treatment. It provides a holistic and dynamic analytical framework, helping physicians more accurately comprehend the patient’s physiological condition and devise corresponding treatment plans.
Author Introduction:
Professor Xiaoming Cheng, a Chinese medicine physician at the Institute of Integrative Medicine, Harvard Medical School, Executive Associate Editor of New England Journal of Traditional Chinese Medicine, Visiting Professor of Zhejiang Chinese Medicine University, special expert of Shanghai Fudan Medical College and Huashan Hospital, holographic life system integration expert, has been engaged in Chinese medicine teaching, research and clinical work for 45 years at home and abroad.
He is the author of the English version of Acupuncture and Moxibustion Clinical Desk Reference and the Chinese version of Ten Lectures on TCM Methodology.
八綱辨證法——差异診斷的八大原則
程曉明
摘要：八綱辨證法包括表裏辨证、寒熱辨证、虚實辨证和陰陽辨证。這些差异診斷方法用於確定病變的性質和位置。通過觀察、聽診、嗅診、詢問、脈診和按診等手段，對身體、元氣和病原體之間的衝突進行評估，從而進行八大原則的診斷。
表里辨证法
這種差异診斷方法用於確定病原體的位置和疾病發展的可能性（即轉化的潜力）。
主要的症候如下:
外感证
這是由六淫通過皮膚、毛髮、口腔或鼻子攻擊身體表面引起的症候群。它突然發作，表現爲表淺（僅限於表面），性質温和，大多數情况下持續時間短，通常不影響臟腑功能。
内傷证
與外感证相反，内傷证的特徵是内臟器官的病理變化。内傷证可能是由病原體引起的，這些病原體可以從體外進入或傳入體内，也可以通過直接侵入臟腑引起。内傷证也可能由一些“内在因素”引起，例如情緒不安、飲食不當或心理壓力，直接影響臟腑功能。
外感证轉爲内傷证
這指的是病原體從身體表面深層侵入，或者外感证被内傷证替代的情况。患有外感证的患者可能表現出發熱和寒戰等症狀，舌頭可能正常，有白色薄膜和浮脈。如果寒戰的感覺被熱感所替代，那麽可能出現新的症狀，包括口渴、尿少而深色、舌頭發紅且有黄色薄膜以及脈搏加速，這表明疾病已經表現爲由病原體從體表深部侵入引起的内傷熱证。
内傷证轉爲外感证
這指的是病因因素從内部被帶出到身體的表面的情况。
例如，對於由内熱引起的内傷证，首先出現的症狀可能是煩躁、氣短、咳嗽和胸悶。然後症狀逐漸發展爲發熱和出汗，煩躁减輕或出現皮疹。
這些症狀表明病原體已經被帶到表面，内傷证已經减輕。這通常是由於適當及時的治療和適當的護理，有助於增强身體的扺抗力。病原體從内部傳播到外部表明疾病康復，疾病狀况已經减輕。
内外合病证
這指的是患者同時出現外感证和内傷证特徵的情况。在疾病的初期階段，既可能出現外感证的症狀，如發熱、寒戰、頭痛和全身酸痛，同時也可能出現内傷证的症狀，如上腹脹悶、食慾喪失、腹瀉、舌苔厚白等。
這是由外在病因寒邪和内在病因濕邪的侵襲引起的。
寒熱证的辨證診斷
這是一種區分疾病性質的方法。它與陰陽虚實的區分相同，因爲寒熱是身體陰陽虚實的表現。
主要的症候有
寒证
這種证可以是由寒邪侵襲引起的，也稱爲寒邪過盛。另一種寒证是内虚寒证，患者總是感到内部寒冷。這是由於陽虚陰盛。寒证的臨床表現包括：寒戰、尋求或渴望温暖、無口渴、面色蒼白、寒冷時蜷縮、尿量多而清，大便稀，舌頭蒼白帶白膜，脈搏緊張或緩慢。
熱证
這是由病原體熱邪侵襲或因陰虚陽盛而導致身體亢進引起的证候。臨床表現包括發熱、對熱的厭惡和偏愛冷、口渴喜歡冷飲、面紅、眼充血、煩躁、尿少而深色、便秘、舌頭發紅帶干褐色膜和脈搏快速。
寒熱证同時存在
這意味着一個患者身上同時出現寒证和熱证。這可能表現爲器官失調，上半身爲熱证，下半身爲寒证，或者可能出現在器官本身。
在外感证和内傷证同時出現的情况下，外感证在外部表現爲熱证，内傷证在内部表現爲寒证，反之亦然。
寒证和熱证的轉化
這指的是疾病性質的改變。從寒证轉變爲熱证，例如，當寒邪侵襲身體時，我們可以看到發熱、寒戰、無汗、頭痛、全身酸痛、舌頭薄白膜、脈搏浮而緊等症狀。隨着病理變化的進一步發展，寒戰消失但發熱不减，而對熱的厭惡取代了對寒的厭惡。此外，還逐漸出現其他症狀，如煩躁、口渴和舌頭黄膜，表明外寒证已經轉變爲内熱证。另一方面，疾病最初可能表現爲熱证，隨後發展爲寒证。這種熱证轉變爲寒证的情况在患者由於延遲治療或誤診導致高熱時可能發生。患者可能被病原體壓倒，傷及元氣，突然出現四肢寒冷、大量冷汗、煩躁和脈搏虚弱的症狀。這也被稱爲陽氣崩潰。
伴有假寒症狀的熱证
在這種证候中，疾病具有熱证的特性，但也表現出一些寒症狀，如四肢寒冷、脈搏沉等。它與寒证不同之處在於患者的身體盡管四肢寒冷，但仍然温暖，對熱有厭惡而非對寒，脈搏深但也快而有力。患者還可能有過度口渴、喜歡冷飲、喉嚨乾燥、口臭、神志恍惚、尿少而深色、乾燥的大便或帶有直腸攣縮的熱型痢疾，舌頭呈暗紅色帶有乾燥的黄膜等症狀。在這種情况下，四肢寒冷和脈搏沉被認爲是“虚假的表現”，因爲内熱是疾病的本質。這種情况歸因於體内的過度熱，使得陰表現得表淺。這就是所謂的“由内部過度陽使陰表淺”的情况。
伴有假熱症狀的寒证
在這種情况下，疾病性質是寒证，但表現出一些熱症狀，如發熱、面紅、口渴和大脈。它與熱证的不同之處在於患者雖然發熱，但希望被蓋着，感到口渴但喜歡熱飲，脈搏大但虚弱。可能會觀察到寒症狀，如四肢寒冷、尿清、大便稀，舌頭呈淡粉色帶有白膜。這種证候的原因是體内有過度的陰寒，使得陽表現得表淺。這就是所謂的“由内部過度陰使陽表淺的情况。
總體而言，這些寒熱证的差异診斷是中醫辨证施治的基礎之一。
下面繼續介紹一些相關的内容：
内外合病证：這種情况指的是患者同時出現内傷证和外感证的特徵。可能表現爲上半身爲外感证的熱证，下半身爲内傷证的寒证，或者在器官的不同部分同時表現。
寒证和熱证的轉化：這是指疾病性質的變化，可以從寒证轉變爲熱证，反之亦然。這種轉化常常伴隨着病理變化的發展，症狀逐漸改變，而中醫辨证施治則根據這些變化調整治療方案。
熱证伴有假寒症狀：在這種情况下，疾病具有熱证的性質，但同時呈現出一些寒症狀。這種狀態下，四肢寒冷和脈搏沉被認爲是“虚假的表現”，因爲實際上疾病的本質是内部的過度熱。
寒证伴有假熱症狀：在這種情况下，疾病性質是寒证，但同時呈現出一些熱症狀。這種狀態下，發熱和其他熱症狀被認爲是“虚假的表現”，因爲實際上疾病的本質是内部的過度陰寒。
這些寒熱证的差异診斷有助於中醫醫生準確理解病變的性質和位置，從而制定個性化的治療方案。需要强調的是，中醫辨证施治是一門綜合性的醫學科學，治療方案不僅僅基於病因病機，還考慮到個體差异、環境因素和防治兼顧的原則。
虚实辨证
這是一種用於確定體内元氣的强弱和病原體毒性的方法。
虚证
這種证型表現爲元氣的不足。個體可能天生元氣不足。更常見的是，元氣不足是由於生活方式不當、過度、或生活不平衡引起的。例如，不當的飲食可能導致體質虚弱；情緒不安可能損傷臟腑的氣血；性過度可能消耗腎氣；長期患病可能損害元氣。所有這些因素可能導致各種虚证，包括陰陽、氣血、生命精華、體液和臟腑的不足和損傷。臨床表現包括：面色蒼白或發黄、焦慮不安、消瘦疲倦、乏力、不願言談、心悸、氣短、腰膝酸軟、自汗、夜汗、大便尿失禁、按壓可緩解的疼痛、舌頭淡紅少苔，脈搏虚弱或弱。
實证
這種证型表現爲病原體過盛。它可能是由元氣未衰减而致的病原體過多引起的；這種情况導致體内這兩種力量之間的激烈鬥争。實证的主要表現有：强健的體質、高燒、焦躁、大聲喧嘩、腹脹、疼痛、便秘、尿澀灼熱、舌頭粗糙、厚厚的膩苔、脈搏充盈有力。
虚實合病证
這指的是在同一患者身上同時發生虚证和實证的情况。例如，如果虚证占主導地位，並伴隨實证症狀，患者可能表現出血虚失眠，伴有後腦頭痛，這是由於頸部僵硬引起的。
在實证占主導地位，但伴隨虚证症狀的情况下，患者可能患有寒邪，伴有頭痛、全身酸痛和咳嗽，同時還表現出脾虚的症狀，如感覺疲倦、大便稀薄和腹脹。
實证轉化爲虚证
實证表現爲疾病的初期階段。然而，由於治療延遲或誤診，由於疾病長時間，病原體的衰减和元氣的損傷導致它演變成爲虚证。例如，患者患急性腹瀉，未經適當治療或誤診。幾個月後，它轉變爲虚证，即慢性腹瀉。這就是所謂的實证轉爲虚证。
虚证轉化爲實证
在這種情况下，虚证表現爲疾病的早期階段。由於元氣不足，實質性病原體逐漸在體内積累，産生一些實证症狀。例如，老年人的氣虚可能導致體液枯竭和腸道乾燥。這可能導致便秘的實证症狀。這被稱爲虚证導致實证。
實证伴有假虚症狀
這是一種實证型证候，其特點是病原體的積聚，但伴隨着類似虚证的症狀。也被稱爲“虚证極實”的表現。例如，胃腸道中的熱邪滯留或痰食停滯可能導致胃腸氣運動的阻塞。這伴隨着疲倦、寒冷和四肢冰冷的症狀，以及緩慢而隱匿的脈搏。經過仔細檢查，可能會發現其他症狀，如大聲喧嘩、呼吸粗重、脈搏沉而緩慢或隱匿而有力，表明體内病原體的積聚才是疾病的真正本質，而類似虚证的症狀只是虚假現象。
虚证伴有假實症狀
這是一種虚证，但伴隨着類似實证的症狀。也被稱爲“虚证極實的假象”。例如，由於氣血不足，臟腑在消化和輸送養分方面的功能障礙可能産生類似實证的症狀，如腹部飽脹、脹痛、脈搏有力等。然而，經仔細檢查可能發現腹部飽脹輕微而不嚴重。此外，它不持久且可以通過按壓緩解，患者的脈搏是有力但虚弱的，表明臟腑氣血不足是疾病的真正本質。再次强調，類似實证的症狀只是虚假現象。
復雜证候
實证型表層证候：這種证候導致皮膚和肌肉緊綳感，是由病邪侵襲表層引起的。其表現爲皮膚乾燥、無汗、發熱、對寒冷的厭惡、頭痛、全身酸痛、鼻塞，以及脈搏有力而緊張。
虚证型表層证候：這種证候也稱爲“營衛不和”。其臨床表現包括自發性出汗、發熱、對風的厭惡、多汗和緩慢的浮脈。
虚证型寒邪证候：這種证候是由陽氣不足引起的。表現爲疲倦、面色蒼白、對寒冷和四肢冰冷的厭惡、腹痛（受温暖和按壓可緩解）、大便稀薄、頻繁清澈的尿液、氣短和乏力、蒼白的舌頭，以及脈搏虚弱、緩慢而弱。
實证型寒邪证候：這種证候是由體内過度陰寒和陽氣滯留引起的。是由於過度攝取寒冷或生冷食物，或寒邪直接侵襲體内引起的。表現爲對寒冷和四肢冰冷的厭惡、上腹部寒冷和疼痛、腹痛和壓痛、嘔吐水樣液體、腸鳴聲、慢性腹瀉、咳嗽伴有大量淡白痰液、哮喘、舌頭上有白而滑膩的舌苔，以及脈搏緩慢或緊張。
陰陽辨證
陰陽辨證是貫穿八綱辨證的一般指導原則。陰陽原則主導其他六個原則。在没有明確的辨证模式時，可以通過應用陰陽辨證來簡化對患者的分析。
陰陽的基本概念：
陰陽的相互關係： 陰陽是相互依存、相互制約的概念。它們存在於相互關係中，一個相對於另一個而言。身體的平衡依賴於陰陽的平衡。
陰陽的動態變化： 陰陽是動態變化的，它們不是静止不變的。陰陽之間的平衡可以隨着時間、季節、環境等因素而發生變化。
陰陽的相對性： 陰陽是相對的，即一個相對於另一個而存在。在一個具體的情境中，某一方面可能表現爲陰，而在另一方面可能表現爲陽。
陰陽的互相轉化： 陰陽可以相互轉化，即在一定條件下，陰可以轉化爲陽，反之亦然。這種動態平衡有助於維持生理和病理的穩定性。
應用陰陽辨證的情况：
没有明確的辨证模式： 當患者的症狀不明顯屬於八綱辨证中的某一模式時，可以通過陰陽辨證來初步判斷患者的體質和病變特點。
指導整體辨证：陰陽辨證有助於指導整體的辨证過程。瞭解患者體内陰陽的平衡狀况有助於更全面地理解疾病過程。
個體化治療方案：陰陽辨證有助於制定更個體化的治療方案。根據患者體内陰陽失衡的具體情况，調整治療策略以促進身體的平衡。
總的來説，陰陽辨證是中醫辨证施治的基礎，它提供了一種整體性、動態性的分析框架，有助於醫生更準確地理解患者的身體狀况，並制定相應的治療方案。
作者簡介：
程曉明，教授，哈佛醫學院整合醫學研究所 中醫師；浙江中醫藥大學客座教授；上海復旦醫學院、華山醫院特聘專家；全息生命系統集成專家。國內國外從事中醫教學、科研和臨床工作45年。
著有英文版《針灸臨床案頭參考》、中文版《中醫方法論十講》等著作。
