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Source｜China Traditional Chinese Medicine News
Author｜Zhu Guang, Henan University of Traditional Chinese Medicine
The concepts of cold and heat in Traditional Chinese Medicine (TCM) are abstracted from specific phenomena, reflecting the interaction between the human body and material or environmental factors. Therefore, understanding cold and heat cannot be based solely on quantitative indicators but should be contextualized within the theoretical framework of TCM.
As an important concept, cold and heat have extensive applications in TCM, serving as symptoms, disease attributes, causes and mechanisms, and the four qi (temperatures) of medicinal substances. However, influenced by modern ways of thinking, there are many misunderstandings about the cold and heat in TCM. This article aims to clarify these concepts.
Cold and Heat as Causes
Cold and heat are natural phenomena that cycle with the seasons. When there is excess or deficiency, or when the temperature changes abruptly, cold and heat can become pathological.
Cold Pathogen has a nature of stagnation and contraction, obstructing the meridians, which slows the circulation of qi and blood, leading to pain when there is blockage; it constricts the qi mechanism, causing muscle and joint stiffness; and it closes the pores, preventing sweating. Cold can easily deplete yang qi and obstruct it, resulting in a fear of cold.
Heat Pathogen includes fire and summer heat among the six excesses, but does not include heat pathogens. Generally, heat pathogens, also known as “warm pathogens,” are a collective term for pathogenic qi that leads to yang-heat diseases. It is often said that “heat is the gradual increase of fire, and fire is the extreme of heat,” but it should be understood as “heat is the manifestation of fire, and fire is the essence of heat.” In terms of pathogenic characteristics, fire heat is a yang pathogen that easily injures fluids and depletes qi; it tends to rise and can invade the upper body; it can generate wind, and excessive heat can scorch the liver meridian, leading to internal wind, manifesting as tremors and convulsions, and in severe cases, opisthotonos; excessive heat can force blood to move erratically, causing various types of bleeding such as hemoptysis, hematochezia, and skin purpura; it can disturb the spirit, and during high fever, it can lead to delirium; additionally, the “Lingshu: Abscesses and Sores” states: “Excessive heat causes flesh to rot, and rotting flesh leads to pus.” The “Medical Canon of the Golden Mirror” states: “Abscesses and sores originate from fire toxicity, obstructing the meridians and coagulating qi and blood.” As for summer heat, it is the fire heat of summer, which has a clear seasonality, tends to injure fluids and deplete qi, and often carries dampness, presenting a state of high temperature and high humidity.
The constitution formed by congenital and acquired factors is a relatively stable characteristic inherent in the human body in terms of structural form and functional activity, manifested as certain differences in response and adaptation to external stimuli under physiological conditions, as well as susceptibility to certain pathogenic factors and tendencies in disease progression. The internal cold and heat environment, such as yang deficiency constitution, yin deficiency constitution, and damp-heat constitution, plays a background role in the nature and evolution of diseases.
Cold and Heat as Mechanisms
Regarding the cold and heat phenomena in nature, modern explanations state that at different times of the year, the Earth is in different positions in its orbit, receiving varying amounts of sunlight and heat, thus resulting in seasonal changes and temperature differences. Influenced by the ancient philosophy of the correspondence between heaven and humanity, TCM has long recognized the importance of yang qi in the human body. As stated in the “Suwen: On the Vitality of Heaven and Earth”: “Yang qi is like the sky and the sun; if it loses its place, it will shorten life and not manifest.” Yang qi in the human body can nourish the five organs and six bowels, circulate qi and blood, transform fluids, protect the skin, and resist cold, serving as the root of vitality.
TCM believes that the phenomena of cold and heat in the human body are specific reflections of the fluctuations of yin and yang qi, as stated in the “Suwen: On the Correspondence of Yin and Yang”: “When yang prevails, there is heat; when yin prevails, there is cold,” and in the “Suwen: On Regulating the Menstrual Cycle”: “When yang is deficient, there is external cold; when yin is deficient, there is internal heat; when yang is excessive, there is external heat; when yin is excessive, there is internal cold.” Specifically, pathogenic yin can lead to the depletion of yang qi or obstruction of its flow, or it may be due to a pre-existing deficiency of yang qi, resulting in an inability to warm and transform, which can manifest as cold patterns; pathogenic yang can lead to an excess of yang heat, or it may be due to a deficiency of yin fluids, resulting in an inability to restrain yang, leading to an excess of yang qi, which can manifest as heat patterns. In other words, whether relative or absolute, an excess of yin qi results in cold, while an excess of yang qi results in heat. Zhang Jingyue has a profound insight on this: “Cold and heat are transformations of yin and yang.” “When water and fire lose their harmony, it results in cold and heat.”
Cold and Heat as Symptoms
Cold and heat, when used to describe symptoms, refer to the sensations of cold and fever. The fear of cold primarily refers to an abnormal sensation experienced by the patient, while fever can be observed as an increase in body temperature or a subjective feeling of heat without a change in temperature. The “Complete Works of Jingyue” lists the inquiry about cold and heat as the first question, serving as two guiding principles for differentiating the nature of diseases in the eight principles of TCM.
Regarding the fear of cold, there is a distinction between aversion to cold and fear of cold. Generally, it is believed that if the sensation of cold persists despite adding clothing, covering oneself, or warming by the fire, it is termed aversion to cold, which is often a sign of an exterior syndrome; if it can be alleviated, it is termed fear of cold, reflecting either yang deficiency or yang obstruction. If further differentiated, cold experienced normally and throughout the body is often due to yang deficiency, while cold experienced during illness and in specific areas is often due to yang obstruction.
Cold and heat are also direct indicators of the balance of yin and yang, as Zhang Jingyue stated: “Yin and yang are not visible, but cold and heat are evident.” Generally, determining the cold and heat attributes of a disease pattern often requires a comprehensive judgment that combines the deficiency and excess of the pattern.
The basic manifestations of cold patterns include: aversion to cold, fear of cold, cold pain, preference for warmth, pale and moist tongue, clear and long urination, loose stools, and a tight or slow pulse. The basic manifestations of heat patterns include: aversion to heat, preference for cold drinks, red face and eyes, restlessness, yellow and thick phlegm, hemoptysis, short and red urination, dry and hard stools, red tongue with yellow and dry coating, and a rapid pulse.
Cold and heat patterns are fundamentally different yet interrelated; they can appear simultaneously and can transform into one another under certain conditions. In critical stages of disease, false cold or false heat phenomena may even occur.
Mixed Cold and Heat refers to the simultaneous presence of cold and heat patterns, presenting a phenomenon of alternating cold and heat, which can vary by location, with distinctions between upper and lower, exterior and interior. For example, upper cold and lower heat may present as cold pain in the stomach, vomiting clear phlegm, along with frequent urination, painful urination, and short red urination; upper heat and lower cold may present as heat in the chest, sore throat, dry mouth, along with abdominal pain relieved by warmth and loose stools. Exterior cold with interior heat may present as aversion to cold, fever, no sweating, headache, body aches, or shortness of breath, along with sore throat, thirst, yellow urination, and constipation; interior cold with exterior heat may present as fever, headache, cough, along with loose stools, clear and long urination, and cold limbs.
Transformation of Cold and Heat can occur due to internal and external environmental factors. Cold patterns can transform into heat patterns, for example, after exposure to cold, one may experience aversion to cold and fever, with no sweating, white coating, and a tight pulse, followed by the disappearance of aversion to cold and the emergence of high fever, restlessness, thirst, yellow coating, and a rapid pulse; heat patterns can transform into cold patterns, for example, after high fever and profuse sweating, one may experience a sudden drop in body temperature, cold limbs, pale complexion, and a weak pulse.
True and False Cold and Heat can occur when cold or heat patterns develop to extremes, leading to false appearances of cold resembling heat and heat resembling cold. True cold with false heat may present as fever, flushed face, thirst, and a large pulse, yet the patient desires to cover themselves, craves hot drinks but cannot drink much, with a fluctuating red face, and cold limbs, clear urination, and a pale tongue with white coating. True heat with false cold may present as cold hands and feet, a deep pulse, yet the patient does not fear cold but fears heat, with thirst for cold drinks, dry mouth, short and red urination, and dry stools, with a red tongue and yellow coating.
The “Huangdi Neijing” discusses cold and heat with specific names and chapters, such as in the “Suwen: On Wind” stating: “Wind qi is stored between the skin and flesh, unable to circulate internally or leak externally… When it is cold, it leads to loss of appetite; when it is hot, it consumes muscle, causing the person to feel cold and unable to eat, termed cold and heat.” The “Lingshu: Cold and Heat Diseases” discusses the symptoms, treatment, and prognosis of cold and heat diseases affecting the skin, muscles, and bones; the “Lingshu: Cold and Heat” discusses the causes, mechanisms, and prognosis of scrofula caused by the retention of cold and heat toxic qi in the meridians.
Cold and Heat of Medicinal Substances
The “Shennong Bencao Jing” states that medicines have four qi: cold, heat, warm, and cool. The “Complete Works of Jingyue” points out: “Qi originates from heaven… Warm and hot are the yang of heaven; cold and cool are the yin of heaven.” The “Shennong Bencao Jing Shu” also states: “The growth of substances must rely on heaven, and their formation must depend on the earth. Heaven issues commands, governing growth, with cold, heat, warm, and cool being the qi of the four seasons.” In other words, the four qi of medicinal substances are closely related to natural climatic conditions.
The four qi and five flavors of medicinal substances are innate, and their identification in ancient times could only be achieved through “tasting” and “testing,” as stated in the “Shennong Bencao Jing: Record of One Hundred Medicinal Substances”: “By tasting, one knows its flavor; by entering the stomach, one knows its nature.” This means that the properties and flavors of medicines are determined after consumption, using taste and the cold and heat of the disease as reference standards. This is evidently a subjective experience, inevitably influenced by the subjective factors of the perceiver, leading to frequent discrepancies in the judgment of the cold and heat properties of the same medicinal substance. Tao Hongjing lamented this, stating: “It is easy to know whether something is toxic or not, but the distinction of cold and heat must be clear.”
The difference between cold and cool, warm and hot is merely a matter of degree; some herbal literature further distinguishes them using terms like great heat, great cold, mild warmth, and mild coolness. However, in essence, the four properties of medicines are fundamentally just cold and heat.
Cold and Heat in Treatment
Cold and heat are manifestations of the imbalance of yin and yang in the human body. Diseases have cold and heat, and medicines also have cold and heat. Therefore, the “Shennong Bencao Jing” states: “Treat cold with hot medicines, treat heat with cold medicines,” meaning to use the cold and heat properties of medicines to correct the cold and heat of diseases, or “to correct the bias with the bias.” Regarding this, the “Shennong Bencao Jing: Record of One Hundred Medicinal Substances” states: “All medicines… should be used according to their strengths to treat diseases, thus able to supplement the bias and rectify the deficiencies, harmonizing the organs.” The “Jingyue Shishi Yigao” also states: “Use cold medicines to transform the heat of disease, and use hot medicines to transform the cold of disease… This is the principle by which medicines can treat diseases, originating from the yin and yang of the four seasons, embodying the unity of heaven and humanity.”
The treatment principle established in the “Suwen: On the Most Important Principles” is “treat cold with heat, treat heat with cold”; “cold is treated with heat, and heat is treated with cold.” This belongs to the antagonistic treatment in TCM. When implementing this, attention should be paid to: first, distinguishing between deficiency and excess. Generally, real cold should be warmed and dispersed, while deficient cold should be warmed and tonified; real heat (fire) should be cleared and drained, while deficient heat (fire) should be cleared and lowered. Second, distinguishing between true and false, as stated in the “Suwen: On the Most Important Principles”: “Those who are cold and yet hot should take from yin; those who are hot and yet cold should take from yang.” Wang Bing annotated: “Strengthening the master of water to control yang; benefiting the source of fire to eliminate yin shadows.” Third, avoiding the phenomenon of drug rejection, the “Suwen: On the Five Constant Regulations” proposes a solution: “Treat heat with cold, and take it warm; treat cold with heat, and take it cool,” meaning that when using cold medicines to treat heat diseases, they should be taken warm, and when using hot medicines to treat cold diseases, they should be taken cool.
Editor｜Wang Qingyun
Reviewed by｜Bai Xiaoyun, Xu Jing
