TCM Heat and Inflammation

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Article originally published March 24, 2022

In April of 2021, I authored an article about recovery formulas applicable for patients experiencing various symptoms after having survived the acute onset of the current pandemic. In that article, Lingering Evil Qi was discussed as a possible etiology for their ongoing struggles to regain health. Recently, a practitioner contacted Mayway asking for clarification of the difference between Lingering Evil Qi and Latent Heat. Are these ideas the same or different?

Lingering Evil Qi

Inflammation Graphic First, a review from the article, Recovery Formulas for Lingering Evil Qi. In Traditional Chinese Medicine (TCM), Lingering Evil Qi is known as Fú xié 伏邪, literally, “Concealed Evil Qi”. Fú xié was described in both the Shang Han Lun and Wen Bing. Essentially, it is a source of disharmony that remains in the body after recovery from an illness that induces chronic or intermittent clinical signs that are inconsistent with what would be considered normal health. The cause of this disharmony could be a remaining etiological factor (bìng xié 病邪) that has not been completely dispelled or cleared from the body. The original factor that may once have been present has diminished so that only an echo remains. Almost always, nothing can be detected serologically, and the clinical signs often recur when a person is fatigued or stressed, and the individual simply does not feel well. Arguably, the Bìng xié may indeed be absent and the disharmony is a natural result of the body’s response to the insult via the functioning of the anti-pathogenic Qi, e.g., damaged tissue due to the inflammatory response of the immune system. Regardless, the result for these individuals is that the Upright Qi (zhèng qì 正氣) is compromised.

When the initial symptoms of Lingering Evil Qi appear, they look like a warm disease, without the formal progression from superficial to deep. Symptoms are characteristic of internal Heat or Damp Heat, Yin damage, Qi deficiency, or possibly Blood stasis. The original etiological factor involved is either Heat or Damp Heat, which have been seemingly dispelled, cleared, or resolved, but remnants settle in the lower Qi, Ying, or Xue Levels, or alternatively, in the Shao Yang, Tai Yin, or Shao Yin Stages. Often, this disharmony is located within a particular level or location in the body and can primarily affect a specific Zang Fu, or sometimes multiple organ systems or tissues, including blood vessels, the brain, and the nervous system.

Heat in the body can be the nature of the etiological factor or the result of any Bìng xié turning into Heat when it encounters the Wèi (衞氣) and Zhèng Qì. A Yang expansive Bìng xié, Heat can quickly change locations. Heat damages the Yin, which may result in Yin deficient Heat, and, at the deeper levels, Heat congeals Blood.

Individuals with Damp constitutions, including those with excess adipose tissue and those who consume damp diets (e.g., high fat and excess alcohol use) are more susceptible to Damp Heat-causing disharmonies. Damp Heat is a mixed Yin and Yang Bing xie. The Heat “cooks” the Damp making it viscous and sticky, while the Dampness is said to “wrap” the Heat, muting its expression and making it more difficult to clear.

Fatigue is a common component of a Lingering Evil Qi. It is usually not related to energy expenditure and may be worse with inactivity and/or sleep. This fatigue may be accompanied with a sense of weakness that is both mental and physical and may include tired and weak muscles, foggy-headedness, and poor concentration.

Latent Heat

Latent heat (潜热 qián rè) as a Chinese medicine concept has ancient origins dating to the Huangdi Nei Jing and the Shang Han Lun, first appearing in Chapters 3 and 5 of the Su Wen. It was used to explain how the exposure of a Cold pathogen, believed to occur in winter, changed to Heat in the spring. The Cold may or may not have caused an acute disease, but when the Yang element arose in the spring, the Cold was transformed in the body into a Heat pattern. The source of this Heat was described as latent, that is, inactive or suspended in growth or development awaiting a “spark” to become active. Primarily, Latent Heat was a theoretical explanation about how a Cold Induced Disorder could become Heat. Later, the context of winter exposure and spring disease was abandoned because the phenomenon of Heat could occur in any season.

Currently, Latent Heat is a useful concept to explain how Internal, Organ, or Blood Heat can arise without obvious disease proceeding through the Four Levels or Six Stages. Various teachers have described examples of Latent Heat that include repressed emotions, especially anger and frustration leading to Liver Heat, Yin deficient Heat, and suppression of symptoms from disease without treating the root cause, et al. In recent years, and certainly not a TCM concept, the idea that vaccines or immunizations can cause Latent Heat has been suggested. This being due to the antibodies created from the adaptive response to the vaccine kill the pathogen without expelling it or engaging the innate immune system, which includes the healing of damaged tissue at the end of a “normal” disease process. Other proposed sources of Latent Heat include recreational (or in some cases, prescription) drug use including alcohol, tobacco, cannabis, et al., heavy metals, pesticides, and other vaguely named “toxins” (see below).

Latent Heat as a source of disease can thus be understood in terms of its inflammatory effects. What exactly then is inflammation and how does it relate to Heat in TCM? The two concepts are closely related, and a discussion of inflammation may aid in the understanding of Heat in TCM.


Inflammation is one of the primary strategic features of the immune system. Inflammation is a protective response by cells and tissues that have been damaged by pathogenic influences including viruses, bacteria, fungi, and allergens; chemical irritants such as heavy metals, pesticides, endocrine mimetics (e.g., phthalates), chlorinated hydrocarbons, dioxins, PCBs (polychlorinated biphenyls), et al.; thermal and chemical burns; ionizing radiative sources such as ultraviolet, x-rays, and gamma rays; trauma, and more. The function of inflammation is to eliminate the initial cause of the cell injury, remove damaged or necrotic cells and/or tissue that result from the inflammation, and, importantly, initiate the repair mechanism and healing.

The five easily observed signs and symptoms of inflammation are heat (increase in temperature, locally or systemic, which may include fever and/or diaphoresis), redness, swelling, pain, and loss of function. The redness and heat are due to the vasodilation of arterioles and a localized increase in blood flow. This results in increased oxygen perfusion and metabolic activity, both of which are critical to healing and resolution. The swelling and pain are caused by increased capillary permeability and exudate formation with accompanying serum proteins, which signal a pain response to the CNS (Central Nervous System), and clotting factors. The swelling and pain also cause reduced function and promote rest, which is necessary for healing.

When there is an insufficient or inadequate inflammatory response, this can lead to progressive tissue damage being caused by the pathogen, irritant, or other harmful stimulus, which can lead to severe tissue damage, organ failure, or death of the organism. If the inflammation is unable to be controlled, the result can be chronic disease such as irritable bowel syndrome, atherosclerosis, or so-called auto-immune diseases.

The Immune System

Although we tend to think of the immune system as a “thing”, it is incredibly complex, as the name “system” implies. Also, there is a tendency in TCM circles to equate the TCM concept of Wèi Qì (衞氣)with the immune system, which can lead to confusion and oversimplification. While there are obvious areas of conceptual overlap, the biomedical “immune system” must include other types of Qi plus aspects of the TCM concepts of Blood, Yin, and Marrow to be properly understood. The following is intended to touch on the highlights and is not meant to be comprehensive.

The first line of defense in protecting the body is barrier immunity. The prevention of the entry of harmful substances falls on the various physical and chemical properties found on or near the surface of the body. These passive barriers include the skin, mucous membranes, saliva, tears, stomach acid, and urine. If these barriers are unable to keep pathogens out of the body, the active immunity is engaged.

Active immunity is comprised of innate and adaptive immunity, and both are characterized by humoral and cell-mediated components. Inflammation is activated by the second part of innate immunity when the barriers to harmful agents have been breached. Cell and tissue injury initiate the release of polymorphonuclear leukocytes (white blood cells) that are responsible for the creation of chemical mediators including histamines, prostaglandins, thromboxanes, cytokines, leukotrienes, and several more. These chemicals cause the constriction of blood vessels, capillaries, bronchiolar smooth muscle cells, vasodilation, and attract eosinophiles and more polymorphonuclear leukocytes. Among the leukocytic immune cells are monocytes (precursor leukocytes), neutrophils and macrophages (both of which are phagocytes that engulf and digest foreign cells), basophils and eosinophils (both of which are inflammatory cells and are often found in allergic reactions). Another lymphocytic cell associated with innate immunity is the natural killer cell (NK) that targets infected body cells by detecting changes in surface receptors of previously healthy cells and then destroying those cells. Collectively, these chemicals and cells create the five cardinal signs of inflammation mentioned above.

This acute response is intended to rid the host of the foreign agents that induced the inflammatory response. In addition to the cell-mediated action of leukocytes, there are specialized serum proteins that circulate freely in blood (the humoral component), known as the complement system, which attack and destroy microbes by recognizing cellular receptors (also proteins) found on the microbe or when pathogens have been bound by antibodies. There is an increased blood flow to the injured area and the swelling is bound by cells engaged in phagocytosis, fibrin from clotted blood, and leukocytes involved in tissue repair. Ideally, there will be complete restoration of the inflamed tissue back to normal status. Inflammatory measures such as vasodilation, chemical production, and leukocyte infiltration cease, and damaged cells regenerate or are replaced with healthy tissue. 

When there are substantial amounts of tissue destruction, or when the damage in tissues cannot be regenerated, fibrous scarring occurs in these areas of damage, forming a scar that is composed primarily of collagen. The scar tissue may also cause functional impairment.

Sometimes, the influx of polymorphonuclear leukocytes, serum proteins and fluid, live and dead cells, tissue debris, and the infectious agent are contained in a purulent abscess. The liquid suspension contained within the abscess is commonly referred to as pus. Over time, the abscess is usually resolved during treatment for the pathogen. Otherwise, aspiration or surgical resection may be necessary.

In vertebrates, the adaptive immune system is acquired over the life of the organism in which this subset of immunity prepares the body for pathogens it has already encountered. Adaptive immunity relies on the capacity of immune cells to distinguish between the body’s own cells and pathogens. Antigens can be proteins, peptide chains, polysaccharides, lipids, or nucleic acids. Vaccines are externally created antigens that are designed to induce the memory function of the adaptive immune system to combat subsequent introduction of a specific pathogen. The immunity from vaccines can last for months to years. Many vaccines require a booster since the immunity derived from this challenge can wane.

The adaptive response is carried out by two types of lymphocytes known as B cells and T cells, which are produced by stem cells in bone marrow. T cells are further developed in the thymus. There are several types of T cells including CD4+ “Helper” cells which manage the immune response and CD8+ “Killer” cells which destroy cells identified as “not self”.

When B cells are activated by antigens, they secrete antibodies, which are immunoglobulin proteins. There are five types of antibodies: IgA, IgD, IgE, IgG, and IgM, which have biological properties that have evolved to recognize unique antigens and to neutralize specific pathogens.

Interestingly, the adaptive immune system only induces inflammation when the debris from cells which have undergone apoptosis is not resolved or in cases of autoimmunity. Vaccines only rarely create inflammation, except when there is an allergic reaction to components of the vaccine.

Chronic Inflammation

If the injurious agent persists, or if the innate healing offered by the actions of the immune response fails, then chronic inflammation occurs, which is a common feature of many chronic diseases such as diabetes, asthma, cancer, cardiovascular diseases including arteriosclerosis, COPD, chronic kidney disease, allergies, and many others. Macrophages, lymphocytes, and antibody-producing plasma cells predominate in chronic inflammation in contrast to neutrophils in acute inflammation. Chronic inflammation also results when the innate inflammatory response is not actively terminated. Otherwise, nearby cells and tissue may be damaged or destroyed by the inflammatory process. The presence of this damage engenders a continuing inflammatory response.

The resolution of the inflammatory response occurs via several different mechanisms including the relative short half-life of all the inflammatory mediators, which usually operate for 4-9 days. Biomedical strategies include the use of anti-inflammatory drugs such as nonsteroidal anti-inflammatories (NSAIDs) and steroidal-based drugs such as prednisone or hydrocortisone, which are synthetic glucocorticoids and derivatives of natural cortisone. NSAIDs act by inhibition of the enzyme cyclooxygenase, which is necessary for the synthesis and release of prostaglandins and thromboxanes and by inhibiting the activation of neutrophils, which provoke inflammation by releasing other chemical messengers. NSAIDS are accompanied by potential adverse effects of gastric mucosa, renal hemodynamics, electrolytes, cardiac rhythms, thromboembolic events, and antiplatelet activity. Prednisone is widely used because it is a powerful suppressor of a wide variety of inflammatory events and for its ability to suppress autoimmune diseases. Prednisone can cause high blood glucose levels, hypertension, fluid retention (edema), depression, and anxiety in the short term. Long term effects include weight gain, NIDDM, osteoporosis, Cushing’s syndrome, and many others.

Nearly everyone, at some point in their lives, encounters a Heat pathogen attacking the Wei Level (衞分). In traditional Chinese medicine, this may be clinically described as Wind Heat or Toxic Heat, and the treatment principle is to use cool, acrid herbs that release the exterior. In TCM, the Clear Heat category of herbs is one of the largest in the materia medica. Some are cold herbs that Drain Fire from the Lungs, Liver, or Stomach. Some are cold, bitter, salty, or sweet herbs that Cool Blood. Others are cold and bitter herbs that Clear Heat and Drain Dampness or the large category of cold herbs that resolve Fire Toxin, which is used to describe diverse types of virulent infections including various viruses. Finally, there are bitter, sweet, or salty cold herbs that clear Heat due to Yin deficiency. These herbs work by working with the body’s immune system, facilitating the innate inflammatory response, controlling, or limiting the extent of the inflammation, and promoting the healing of infected tissue.

It has been estimated that 60% of Americans suffer from at least one chronic inflammatory condition. This condition of chronic inflammation is not simply a deficiency of Wei Qi, although that may be present. Degrees of Qi, Yin, and Blood deficiency are also found in such patients, which then require the use of herbs from those corresponding categories. As described above, these deficiencies develop from lifestyle choices that include cigarette smoking, alcohol and recreational drug use, obesity, poor diet, lack of adequate sleep, inadequate hydration, stress, and exposure to environmental toxins found in air, water, and food.

In conclusion, it seems apparent that the TCM concept of Heat encompasses both Lingering Pathogen and Latent Heat and is closely related to the numerous ways that inflammation is used by the body to rid itself of and heal from harmful influences. Following the treatment principle of first removing excess, this means that the main task is to clear Heat from whatever etiological cause, not only combating External Pathogenic Influences that cause infectious disease, but also the removal or mitigation of other environmental toxins, as well. Consideration must then focus on ensuring that any deficiencies caused by the employment of the innate and adaptive immune system are supported and tonified. Otherwise, these chronic diseases that are prevalent in today’s world may prove intractable.


Bio: Skye Sturgeon, DAOM

Skye is the Quality Assurance Manager and Special Consultant for Mayway, USA. Skye was the former Chair of Acupuncture & East Asian Medicine and core faculty member at Bastyr University, core faculty member and Faculty Council Chair at the American College of Traditional Chinese Medicine, and President and Senior Professor of the Acupuncture & Integrative Medicine College, Berkeley. Before making Chinese medicine his career choice, Skye held various positions in the Natural Foods Industry for 12 years and prior to that was a clinical biochemist and toxicologist.
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