This article is summarized and organized based on the “Lectures on Basic Theories of Traditional Chinese Medicine” by Li Dexin and “Lectures on Formulas” by Wang Mianzhi published by Renwei Press. Fire Evil is a type of pathogenic qi among the six external evils, characterized by its ability to cause inflammation, consume qi, injure body fluids, generate wind, disturb the heart and spirit.Natural characteristics: Fire has a hot nature, is predominant in summer, and is governed by the four solar terms from Spring Equinox, Qingming, Grain Rain, to the Beginning of Summer. Since summer is dominated by fire, it corresponds with the heart qi; however, fire does not exhibit the same seasonal characteristics as summer heat and is not restricted by seasonal climate.Relationship between warmth, heat, fire, and hot: The four entities of warmth, heat, fire, and hot share similar properties but also have distinctions.Warmth and heat: Here, warmth and heat refer to pathogenic factors. Warmth is a gradual heat, while heat is an extreme of warmth; the two differ only in degree, with no essential distinction, hence they are often referred to collectively as warmth-heat.In the study of warm diseases, the term warm evil also refers to warmth-heat, which encompasses various pathogenic factors such as spring warmth, wind warmth, damp warmth, autumn dryness, warm toxins, and warm syndromes. It generally refers to all warmth-heat evils, without regard to differences in degree.Heat and summer heat: Heat evil, also known as fire heat, is characterized by pathogenic changes that are hot, yang, and solid. Summer heat is the primary qi of summer, transformed from fire heat, thus summer heat is indeed a heat evil. However, summer heat is only present in summer and is purely an external evil, with no concept of internal summer heat. Fire heat, as a disease, does not exhibit obvious seasonal characteristics and also includes high temperatures and the effects of fire heat.Fire and heat: Fire is the source of heat, and heat is the nature of fire. Both fire and heat fundamentally represent an excess of yang, hence they are often referred to collectively as fire heat. However, there are still certain distinctions; heat is purely a pathogenic factor, with no concept of righteous qi, while fire can refer to the body’s righteous qi, termed “less fire”; or it can refer to pathogenic evil, termed “strong fire”, which is the main distinction between fire and heat.Generally speaking, heat often belongs to external pathogens, such as wind-heat, summer heat, and warm heat. In contrast, fire often arises internally, commonly due to imbalances in the yin-yang, qi, and blood of the organs, such as heart fire flaring upwards, liver fire blazing, or gallbladder fire counterflowing.Regarding warmth, heat, and fire, although they are all one qi, warmth can transform into heat, and heat can generate fire, indicating that there are still certain differences in degree. Warmth is a mild heat, heat is an extreme of warmth; heat is a gradual fire, and fire is the extreme of heat.Classification of fire: In Traditional Chinese Medicine, fire is classified into physiological and pathological, internal fire and external fire.
①Physiological fire: Physiological fire is a type of yang qi necessary for maintaining normal life in the body, hidden within the organs, and has a warming and transformative effect. This beneficial yang qi is referred to as “less fire”, belonging to the category of righteous qi.②Pathological fire: Pathological fire refers to excessive yang, which consumes the body’s righteous qi, also known as “strong fire”. This pathological fire can be further divided into internal fire and external fire.External fire: It arises from the invasion of warm and hot evils; it can also transform from external evils such as wind, cold, summer heat, dampness, and dryness, known as “the five qi transforming into fire”.Among the five qi, only summer heat is purely an external fire, referred to as summer heat; the other evils of wind, cold, dampness, and dryness are not fire heat evils, but can transform into fire under certain conditions.First, the stagnation must transform into fire. Wind, cold, dampness, and dryness invade the body and must stagnate for a long time to transform into fire.For example, cold can transform into heat, extreme heat generates fire, warmth and heat can combine, or dampness can transform into heat, where heat becomes more intense due to dampness, leading to difficulty in resolving heat, stagnation transforms into fire, or dampness can transform into heat, where excessive damp-heat transforms into fire. Fire is dry, hence dryness can also transform.Second, it varies by individual; those with excessive yang or deficient yin are more prone to transform into fire.Third, it relates to the location of the evil invasion. For instance, if the evil invades the Yangming dryness soil, it is easy to transform into fire; if the cold evil directly enters the spleen, it is also difficult to transform into fire. Additionally, whether the five qi can transform into fire is also related to treatment.Internal fire: Internal fire often arises from dysfunction of the organs, imbalance of yin-yang, qi, and blood, and excessive emotional distress can also lead to prolonged stagnation transforming into fire, known as “the five emotions transforming into fire”.Traditional Chinese Medicine classifies fire into righteous and evil types; the righteous qi fire is less fire, which can be further divided into “ruler fire” and “minister fire”. “Ruler fire” refers to the yang qi of the heart, while “minister fire” refers to the yang qi of the liver, kidney, gallbladder, bladder, pericardium, and sanjiao, among which the yang qi of the kidney is also called “mingmen fire” or “dragon fire”, and the yang qi of the liver is called “thunder fire”.“Ruler fire” refers only to righteous qi; if it is overly vigorous, it becomes “heart fire blazing”; while minister fire encompasses both righteous and evil aspects, when overly vigorous it is termed “minister fire in disorder”. Both “heart fire blazing” and “minister fire in disorder” belong to “strong fire”, which is an evil qi.Nature and Pathogenic Characteristics of Fire Evil①Fire nature is upwardly inflammatory: Fire evil has a burning and upward nature, and its pathogenic heat signs are significant, often seen in the upper part of the body. Its burning nature means it can scorch and burn.Burning is a characteristic of fire heat evil, which has the property of burning and scorching. Therefore, when fire evil causes disease, the main mechanism is an excess of yang qi, clinically manifested as high fever, aversion to heat, and a rapid pulse, indicating signs of heat excess. In summary, fire heat as a disease is characterized by significant heat signs, with fever and a rapid pulse as its features.Its fire nature is upwardly inflammatory; fire is a yang evil, and its nature is to rise, hence fire evil causing disease has a clear upward inflammatory characteristic, often manifesting in the upper part of the body.For example, if heart fire flares upwards, it can lead to symptoms such as a red and painful tongue tip, oral ulcers, and sores, which can be treated with Dao Chi San (Guide Out the Red Powder) (from “Pediatric Medical Evidence”); if liver fire flares upwards, symptoms such as splitting headaches and red, swollen eyes can be treated with Long Dan Cao Pian (Gentian Decoction) (from “Medical Formula Collection”) or Xiao Chai Hu Tang (Minor Bupleurum Decoction) with modifications, or Xiao Chai Hu Granules combined with Xia Sang Ju Granules or Ban Lan Gen Granules; if stomach fire is excessive, symptoms such as swollen gums and bleeding gums can be treated with Qing Wei San (Clear the Stomach Powder) (from “Lan Shi Mi Cang”).Heart fire flaring upwards can be treated with the heat-clearing formula Dao Chi San, which consists of:Sheng Di Huang (Rehmannia Root) 10g, Chuan Mu Tong (Clearing Wood) 10g, Sheng Gan Cao (Raw Licorice) 10g, Dan Zhu Ye (Lophatherum) 10g, which has the effects of clearing the heart, nourishing yin, and promoting urination.Indications: Heat excess in the heart channel. Symptoms include vexation and heat in the chest, thirst with a desire for cold drinks, and oral ulcers. If heart heat transfers to the small intestine, it can lead to symptoms of painful, red, and burning urination. The heart and small intestine are interrelated; in terms of the five elements, both belong to fire and are red in color. This formula guides heat downward, hence it is called Dao Chi San. Its main symptoms are vexation and heat in the chest, thirst for cold drinks, dark and hot urination, or difficulty urinating, and even oral ulcers, which occur due to fire in the heart or small intestine. The concept of fire in the small intestine arises from the belief in Traditional Chinese Medicine that the small intestine separates clear from turbid, with the turbid entering the large intestine and the clear entering the bladder.The terms clear and turbid refer to two different substances; the clear from food and drink is primarily the nutritive and defensive qi, with the clear among the clear being nutritive and the clear among the turbid being defensive. The turbid descends as urine and the clear as stool, with urine being the clear among the turbid, exiting from the small intestine, and stool being the turbid among the turbid, exiting from the large intestine, which is the explanation from the past.From this perspective of clear and turbid, it still has relevance to the current function of the small intestine. In the entire digestive absorption process of the body, the function of the small intestine is very important, hence the small intestine is referred to as the “official of receiving abundance”; it is not the “official of transmission”, as the large intestine is the “official of transmission”. From this issue, it can be seen that the ancients had a certain understanding of the organs.Here, through Dao Chi San, the relationship between urination and the small intestine is also mentioned, as these issues are related to Dao Chi San.The focus is on the fact that the symptoms of Dao Chi San arise from the heat of the heart channel descending to the small intestine.The heat of the heart channel can arise from various causes; in adults, it is mainly due to emotional distress, the fire of the five emotions, overthinking, kidney fatigue, heart yin deficiency, and excessive heart fire, leading to the downward transfer of heart fire to the small intestine, resulting in vexation in the heart, even oral ulcers, thirst with a desire for cold drinks, and a flushed face, but this is not the key point for differentiation.The key point is to observe the urination; if there is vexation and heat in the heart, children may show restlessness, with body heat not being high, then Dao Chi San should be used to expel heat through urination.However, it is important to note that the heart is a fire organ; once the disease is resolved after taking the medicine, it should be stopped immediately to avoid excessive use of the medicine damaging the heart yang and causing other diseases.Qing Xin Lian Zi Yin (Clear Heart Lotus Seed Decoction) (from “Taiping Huimin Heji Bureau Formula”): Huang Qin (Scutellaria) 15g, Mai Men Dong (Ophiopogon) without heart 15g, Di Gu Pi (Lycium) 15g, Che Qian Zi (Plantago) 15g, Gan Cao (Licorice) 15g, Shi Lian Rou (Lotus Seed) without heart 22g, Bai Fu Ling (Poria) 22g, Huang Qi (Astragalus) honey-fried 22g, Ren Shen (Ginseng) 22g.Usage: Grind and mix, take three qian (about 9g), add ten grains of Mai Men Dong, with one and a half cups of water, decoct to eight parts, remove the residue, cool in water, and take before meals. If there is fever, add Chai Hu (Bupleurum) and Bo He (Mint) for decoction.Function: Benefits qi and yin, clears heart fire, and stops turbid urination.Original indications: Accumulation in the heart, often causing restlessness, due to overthinking and labor, worry and depression, leading to turbid urination, or sand-like membranes, nocturnal emissions, painful urination, or red urination like blood; or due to excessive indulgence in alcohol and sex, with excess above and deficiency below, heart fire flaring upwards, lung metal being constrained, dry mouth and tongue, gradually leading to thirst, restless sleep, fatigue in the limbs, men with five types of urination, women with red and white discharge, and failure to recover after illness, with yang floating outward, and five hearts feeling hot. The properties of the medicine are warm and balanced, neither cold nor hot. Regular use clears the heart and nourishes the spirit, replenishes essence and relieves deficiency, moistens the intestines and stomach, and regulates qi and blood.This formula treats internal heat. Due to internal heat (here referring to heart heat), it leads to excessive heart fire, with the heart and kidney not communicating, water and fire not being able to harmonize, meaning heart fire cannot descend to the kidney, and kidney water cannot ascend to the heart. This situation leads to instability of the essence barrier, resulting in abnormal urination, even leading to nocturnal emissions, which is not due to damp-heat descending.This formula does not contain herbs to expel damp-heat; the disease belongs to internal injury, caused by excessive thinking. This formula is an excellent remedy for clearing the heart and kidney, benefiting both qi and yin, and nourishing both heart and kidney. At first glance, this formula may seem to have a chaotic selection of herbs, as it includes Mai Men Dong, and during decoction, it also adds Mai Men Dong, which highlights the characteristics of Mai Men Dong and the focus of this formula on the heart and kidney while also addressing the liver and small intestine, and in clinical practice, it is quite effective.However, care must be taken to distinguish it from damp-heat descending.Long Dan Xie Gan Tang (Gentian Decoction) (from “Medical Formula Collection”)【Composition】Long Dan Cao (Gentian) stir-fried 6g, Huang Qin (Scutellaria) stir-fried 9g, Zhi Zi (Gardenia) stir-fried 9g, Ze Xie (Alisma) 12g, Mu Tong (Akebia) 9g, Che Qian Zi (Plantago) 9g, Dang Gui (Angelica) washed with wine 3g, Sheng Di Huang (Rehmannia) stir-fried 9g, Chai Hu (Bupleurum) 6g, Sheng Gan Cao (Licorice) 6g.【Usage】The original text does not specify usage and dosage. Clinically, it is generally decocted in water, with the dosage determined by the severity of the condition. It can also be made into pills, with each dose being 6-9g, taken twice daily with warm water.【Function】Drains liver and gallbladder excess fire, clears damp-heat from the lower jiao.【Indications】Excess fire disturbing the liver and gallbladder. Symptoms include headaches, red eyes, rib pain, bitter mouth, deafness, ear swelling; or damp-heat descending, with symptoms of genital swelling and itching, muscle atrophy, dark and turbid urination, and women’s damp-heat discharge.Long Dan Xie Gan Tang uses Sheng Di and Dang Gui, primarily treating the liver, where excessive liver fire has transformed into heat; although liver fire is excessive, the liver itself must store blood, being yin and using yang; it is precisely because the yin blood is sufficient that liver qi can flow smoothly and not become excessive. All treatments, despite being for excess fire, also use some yin-blood tonifying herbs to ensure that draining fire does not damage the liver’s body; prolonged use of bitter-cold herbs can also dry and injure yin.This is based on the characteristics of the liver; the nature of Chai Hu is similar; since the liver’s excess must be drained, it must also be regulated. If it is forcibly suppressed, it will rebound even more severely; hence sometimes using liver-soothing or liver-draining herbs can lead to increased excess. This is because the liver governs rising, and the liver body is yin while using yang, favoring smooth flow and drainage, which determines these characteristics. Therefore, appropriate pairing with Chai Hu can allow for the draining of Long Dan Cao without damaging liver qi; this principle is consistent with the need for liver-soothing herbs in the formula for calming liver wind. However, the methods of application differ; one manifests in the upper body, with red eyes, headaches, ear swelling, ear deafness, bitter mouth, and chest pain, requiring the medicine to act upwards, better following the liver channel. Chai Hu plays a guiding role. In specific applications, flexibility in pairing is necessary; if the disease is in the upper body, do not use too much Chai Hu; if it is in the lower body, it can be used a bit more.Qing Wei San (Clear the Stomach Powder) (from “Lan Shi Mi Cang”)【Composition】Sheng Di Huang (Rehmannia) 12g, Dang Gui (Angelica) 6g, Mu Dan Pi (Moutan) 9g, Huang Lian (Coptis) 3-5g (increase in summer), generally Huang Lian can be adjusted as needed, and the amount is not fixed; Sheng Ma (Cimicifuga) 6g.【Usage】Grind the above herbs into a powder, take as one dose, with one and a half cups of water, decoct until seven parts remain, remove the residue, and cool to take (modern usage: as a soup, decocted in water, with dosage adjusted according to the original formula proportion).【Function】Clears the stomach and cools the blood.【Indications】Accumulation of heat in the stomach. Symptoms include toothache radiating to the head, facial heat, aversion to heat in the teeth, or gum ulcers, or bleeding gums, or swelling and pain in the lips, tongue, cheeks, and jaw, or hot and foul breath, dry mouth and tongue, red tongue with yellow coating, and a slippery, rapid pulse.【Analysis of the formula】From the name of Qing Wei San and the conditions it treats, it is clear that it addresses heat in the stomach, with turbid heat attacking the teeth, causing toothaches that radiate to the head, along with facial heat, and even gum ulcers or bleeding (i.e., bleeding gums) or swelling and pain in the lips, tongue, cheeks, and jaw, all belonging to the spleen and stomach.This formula should consider why Huang Lian is used instead of Shi Gao (Gypsum). As previously mentioned, with heat in the stomach attacking upwards, the teeth, lips, tongue, cheeks, and jaw are already swollen and have begun to manifest outwardly, thus fire-draining herbs must be used, employing Huang Lian to drain the heart and stomach fire.It is also important to note that although Huang Lian is used at 6g, slightly more than Mu Dan Pi, the last few sentences particularly emphasize increasing the dosage in summer or adjusting it as needed, indicating flexibility in application.If heat is excessive, Huang Lian can be increased, and additional herbs can be added. There is also a theoretical debate, as it is believed that “all pain, itching, and sores belong to the heart”, just as previously discussed regarding Zuo Jin Wan (Left Metal Pill) that “all vomiting and sourness belong to fire”; hence Huang Lian and Dang Gui are used as the main herbs.To treat “all pain, itching, and sores belong to the heart”, it is necessary to drain heart fire and eliminate sores, using Huang Lian and Dang Gui, which is a fixed pairing in the formula.However, here Dang Gui is not the minister herb, because in addition to this, there is also excessive heat; simply using Huang Lian is insufficient, and the heat in the blood has not been eliminated, so while using bitter-draining herbs, Mu Dan Pi is also included.Mu Dan Pi can cool the blood and disperse stasis, hence these two herbs are used together.These two herbs complement each other, and then Sheng Di Huang and Dang Gui are added as the main herbs to cool the blood and clear the heart, while Dang Gui can also nourish the blood.These two combined are emphasized because the treatment is not only for pain but also for swelling, ulceration, and bleeding. On this basis, Sheng Ma is added to “disperse fire”. It can be seen that “dispersing fire” is done on the premise of clearing, rather than simply using dispersing methods when fire is stagnant inside, as that would only provoke the fire without any clearing or draining herbs, leading to uncontrollable fire. How to pair and apply requires careful attention. Just as guiding fire back to its source can easily lead to mistakes; knowing there is false fire, we use Gui Zhi (Cinnamon) and Fu Zi (Aconite) to guide fire back to its source. However, the result may not return to the source, but rather provoke fire first, so it is essential to use paired herbs to control it.Additionally, regarding the first sentence of the indications, toothache radiating to the head is a situation often seen in clinical practice, as all trigeminal neuralgia can be caused by the lower branch; in such cases, adding Shi Gao or adding Zhen Zhu Mu (Mother of Pearl) can be beneficial; if the headache is severe, Di Gu Pi (Lycium) can also be added. Toothaches, whether swollen or not, sometimes accompanied by aversion to cold and heat, can all be treated with this formula. ②Consumption of qi and injury to body fluids: Fire evil has the nature of consuming righteous qi and depleting yin fluids, leading to pathogenic conditions characterized by both qi and fluid deficiency. The fire heat evil, steaming internally, easily forces fluids to leak out, consuming and depleting body fluids, resulting in the clinical manifestations of thirst, preference for drinking, dry throat, short and red urination, and constipation, indicating fluid depletion.When fire is too vigorous, qi may decline in response; excessive yang heat leads to strong fire, which can most easily damage the body’s righteous qi, resulting in a decline in physiological functions throughout the body. Additionally, qi is generated from water, and water can transform into qi; when fire forces fluids to leak, insufficient fluids lead to qi deficiency, such as when excessive fire heat is present, along with strong heat, sweating, and thirst, one may also see symptoms of qi deficiency such as fatigue, lack of speech, and weakness in the limbs.In summary, fire evil harms the body either by directly damaging the righteous qi or by causing fluid damage that leads to qi damage, ultimately resulting in the pathological outcome of fluid damage and qi depletion.③Fire easily generates wind: Fire evil has the nature of disturbing liver wind, leading to the pathogenic condition of extreme wind generated by internal liver wind. When the fire heat evil invades the body, it often scorches the liver channel, consuming fluids and blood, causing the vessels to lose nourishment, leading to internal movement of liver wind, termed “extreme heat generating wind”. Wind and fire stir each other, with symptoms being urgent; clinically, this manifests as high fever, delirium, convulsions, stiff neck, opisthotonos, and upward gaze.Common formulas used for wind occurring in heat diseases include Ling Jiao Gou Teng Tang (Antelope Horn and Uncaria Decoction) (from “Common Cold and Fever Theory”).④Fire easily moves blood: Fire evil has the nature of scorching vessels and forcing blood to move erratically, leading to bleeding and rashes. Blood congeals in cold and flows in warmth; fire heat evil scorches vessels and accelerates blood flow, forcing blood to move erratically, easily causing various types of bleeding, such as hemoptysis, epistaxis, hematochezia, hematuria, as well as skin rashes, excessive menstruation in women, and metrorrhagia. Formulas with cooling blood and stopping bleeding effects can treat blood heat causing erratic movement, such as Shi Hui San (Ten Ash Powder) (from “Ten Medicinal Divine Books”).⑤Easy to disturb the heart and spirit: Fire evil has the nature of easily disturbing the heart and spirit, leading to the condition of the heart and spirit being unsettled. Fire corresponds with heart qi, which governs blood vessels and houses the spirit; thus, when fire evil harms the body, it most easily disturbs the spirit, leading to symptoms such as irritability, insomnia, agitation, and even delirium. Reference can be made to Qing Gong Tang (Clear Palace Decoction) (from “Warm Disease Differentiation”), which has the effects of clearing the heart, detoxifying, nourishing yin, and generating fluids, indicated for warm diseases with mis-sweating, fluid injury, and evil invading the pericardium, presenting with fever, delirium, etc.Or Qing Ying Tang (Clear Nutrient Decoction) (from “Warm Disease Differentiation”), which has the effects of clearing nutrients and penetrating heat, nourishing yin, and invigorating blood, indicated for evil heat transmitting to the nutrients, with symptoms of high fever at night, irritability, little sleep, occasional delirium, eyes often open or closed, thirst or no thirst, or subtle rashes, rapid pulse, and a dry, crimson tongue.⑥Easy to cause swelling and sores: Fire heat evil entering the blood, accumulating in local areas, corrupting flesh and blood, leads to the formation of boils and sores.“Boils and sores are originally caused by fire toxins, with meridians obstructing qi and blood coagulating”; “fire toxins” and “heat toxins” are common causes of sores, with clinical manifestations characterized by localized redness, swelling, heat, and pain.Reference can be made to Xian Fang Huo Ming Yin (Immortal Formula for Life) (from “Effective Prescriptions for Women”), which has the effects of clearing heat, detoxifying, reducing swelling, and promoting suppuration, indicated for the initial onset of sores and swellings due to heat toxins accumulating, with symptoms of redness, swelling, and pain, or fever with chills, thin white or yellow coating, and a rapid, strong pulse. In summary, Traditional Chinese Medicine classifies fire into righteous and evil types, with physiological fire and pathological fire. As Zhang Jingyue said, “Fire is the yang qi of heaven and earth. Without this fire, nothing can be born; without this fire, there can be no life. Therefore, the birth of all things is due to yang qi. However, the harmonious qi gives life, while fierce fire harms life; thus, excessive fire leads to a decline in qi, while peaceful fire allows qi to flourish.” (from “Classified Classics: Yin-Yang Category”)The fire discussed here refers to pathological fire, also known as fire evil. Fire evil can be categorized into external fire and internal fire; external fire arises from external invasion, while internal fire often arises from within.Fire evil is characterized by its burning and upward nature, consuming fluids and qi, generating wind, moving blood, easily causing swelling and sores, and disturbing the heart and spirit. Its pathogenic effects are widespread, with rapid onset, easily spreading like wildfire. Clinically, it presents with high fever, fluid depletion, qi deficiency, liver wind, bleeding, and abnormal mental states.
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