ON THE IMPORTANCE OF PERSPIRATION IN
CHINESE MEDICAL DIAGNOSIS AND THERAPY
There are numerous cases in which traditional Chinese medical texts describe what has been deemed by the authors to be a critical method of applying therapeutic techniques, but such methods are no longer utilized in modern practice. In many cases, there is no explanation for this deletion. Diaphoretic therapy is a good example. This article explores some of the changes that have occurred.
In ancient texts of Chinese medicine, perspiration (diaphoresis) is frequently mentioned as an important sign in the diagnosis of a disease pattern and as a measure of the successful application of a treatment. For example, in scroll 23 of the Ling Shu (1) it is said that in treating hot diseases one should "disperse the hot so that the patient sweats." Also: "When a hot disease has lasted seven or eight days and the Pulse Mouths [site of pulse taking] are agitated and the breaths are short, quickly needle so that sweating will occur in the patient....When a hot disease is complete, and sweating has been achieved but the pulses are still rough and the panting and the fever has returned, do not needle the skin....If there is no perspiration, one cannot needle between the flesh and the skin....When there is a hot disease and sweat has come out, then the pulses are smooth because of the sweating....In a hot disease, the pulses are full and rough but there is no sweating, this means the yang channels are in extremis, then death; yet, if the channels are full and rough and a tranquil sweating can be obtained, then life." In these passages, perspiration is seen as an indicator of the disease status that dictates what types of therapy one might use or avoid, sweating is an intended result of certain treatments, and it is associated with a favorable or unfavorable prognosis.
In the Shang Han Lun (2), a large part of the scroll devoted to Tai Yang disease includes descriptions of the disease state in terms of absence, or presence, of perspiration, as well as inducing perspiration as a therapeutic method. For example: "If treatment of the primary stage of Tai Yang disease with the sweating method does not result in thorough perspiring as desired, the condition shifts to the sunlight yang category....If spontaneous perspiration continues without severe chills, a mild sweating method may be used. In the case the patient has an intensely ruddy complexion, rapid respiration, and cannot lie down, he can be cured by an additional sweating treatment."
Inducing diaphoresis was one of the original three methods of therapy (with emesis and purgation) and later one of the eight methods of therapy (see: Enumerating the methods of therapy) that is still described in textbooks and taught in modern colleges of Chinese medicine. Despite its importance over many centuries, modern literature about treatment strategies, whether describing acupuncture or herbal medicine, rarely mentions induction of perspiration. Further, the diagnostic patterns used to describe various diseases often mention perspiration or its absence only in passing among a long list of possible symptoms, rarely including any discussion of different treatment strategies based on the status of this particular sign. Is this change in emphasis the result of a finding that perspiration is not as important as originally believed, or has something been overlooked simply because of shifts in modern focus to other therapeutic concerns, such as vitalizing blood circulation and regulating the immune system?
As to the role of perspiration as seen by traditional practitioners, consider the following commentary (3) from the Rumen Shiqin (ca. 1228 A.D.):
An illness is something that the human body originally does not have. An illness may enter the body from outside of it, or it may emerge from inside of it....The six influences sent out by heaven are wind, heat, fire, dampness, dryness, and cold. The six influences sent out by earth are fog, dew, rain, hail, ice, and mud...illness resulting from evil influences sent out by heaven affect mostly the upper sections of the body; illnesses resulting from evil influences sent out by the earth affect mostly the lower sections of the body, and illness resulting from evil influences invited by man through his living habits mostly affect the central section of the body. These then are the three possibilities as to how an illness may emerge. Since they may be localized in the three sections they can be driven out by the three methods. All evil influences resulting from an impact of wind or cold assemble in the skin; they are stored inside the main conduits [jing] and network conduits [luo], they remain where they are and do not leave the body by themselves. In some cases they cause pain that moves through the body, or numbness and loss of sensitivity, and also swellings, itching, and cramps in one's four limbs. In all of these cases, the evil influences responsible can be eliminated through therapies causing perspiration....
This passage describes the basis for what we today often call "surface-relieving" or "surface-releasing" therapies-those that help remove evil influences from the skin (and from the jingluo). But what does the induced perspiration do? From the traditional viewpoint, it literally carries the disease out of the body with it. According to Xu Dachun (4): "If no perspiration develops, there is nothing to which the evil influences can attach to leave the body...."
As is understood from reading the Neijing (5), the sweat pores are both the entry and exit point for external evil influences coming from above (heaven). Wind, cold, and heat were the main pathologic influences of concern in relation to perspiration. To treat such ailments, perspiration was induced (if not already profuse), and it was believed that the induced perspiration would carry the pathologic influence out of the body. This was the appropriate therapy only while the pathological influence was still residing in the surface and not mixed in with the "constructive influences," that is, the ying qi.
From these basic ideas of eliminating disease arose the formal category of surface-relieving therapies: their action would be to overcome a contraction of the skin, allowing the pores to open, the perspiration to flow, and the evil influences to be released. As we know today, the blood vessels at the body surface, when affected by diaphoretic herbs or drugs, dilate and permit fluid to exit as perspiration. Surface-relieving formulas not only treat diseases that are confined to the surface, but also diseases for which regulation of perspiration is deemed important. Although not all surface-relieving formulas are intended to induce perspiration (some may simply regulate the circulation in the skin and muscles), many of them were designed to do so.
In the Shang Han Lun, the main formula described for surface ailments, Cinnamon Combination, makes use of the surface-releasing agent cinnamon twig. According to the instructions in the text, the treatment is to be modulated in order to induce a mild perspiration, but it is also used to treat profuse perspiration (it contains the perspiration-controlling ingredient peony). Failure to induce perspiration was thought to condemn the treatment to failure, and excessive perspiration, either as a result of the disease process or the excessive use of sweating therapies, was thought to damage the patient (by removing too much essential fluid). To induce the therapeutic perspiration in someone with only mild spontaneous perspiration (as a sign of disease), the herb decoction would be taken warm, the dosage would be repeated if necessary, and the individual would consume warm rice gruel and bundle-up in blankets. Once some perspiration is induced, efforts to induce it could be stopped (see: Exploring Yin/Yang #5).
The ingestion of rice gruel was deemed an important means of assuring adequate fluid for producing perspiration. Rice (or grains in general) generates stomach qi, replenishing the essential bodily fluids. According to Xu: "Later generations [after the Song Dynasty revival of the Shang Han Lun] were no longer aware of the necessity to support any induced sweating by means of enriching the patient's liquids." The failure to employ this step, especially in the case of a feverish disease which is consuming the normal fluids, can lead to failure to induce perspiration and even to weakening the patient.
Excessive perspiration was considered a problem because the perspiration carried out not only the external pathogen, but some of the essence (jing) of the body. When too much flowed out, the central viscera (zang) became depleted, especially the heart, which has traditionally been considered the source of perspiration (though the Ling Shu describes perspiration from different organs arising under different circumstances). Eventually, the kidney system could be endangered by this depletion of the body's essential fluids. According to Xu: "If one causes the patient to perspire even further, the yang fire reaches its utmost strength and the patients true yin influences are set in motion. The water of the kidneys comes to offer assistance, and it is followed by the original yang influences. The patient perspires profusely in the upper parts of the body, and signs indicating the danger of complete loss of yang emerge."
Much concern was raised in the post-Song Dynasty era about the harm that could be done by applying too many warm spicy herbs, as had become a common practice by following the Shang Han Lun treatment of initial disease stage. Of course, the main complaint was against using these herbs thoughtlessly, without properly diagnosing the patient and figuring out the appropriate treatment, instead simply using formulas that had a reputation for great effectiveness.
The Advanced Textbook on Traditional Chinese Medicine and Pharmacology (6) summarizes the traditional view as it comes down to us today: "The proper dosage of drugs for relieving exterior syndrome causes slight perspiration; overdose can cause excessive perspiration, damage yang qi and consume body fluid. In summer or hot days when people perspire easily, the dosage should be decreased. For patients with spontaneous sweating, night sweating, or blood loss, these drugs should be applied with great care even though the patients suffer from exterior syndrome due to an attack of exogenous pathogenic factors. Most drugs for relieving exterior syndrome are aromatics and contain volatile oils, and so should not be decocted for a long time, otherwise, their therapeutic effects will be reduced." Under the section on surface relieving therapy (as one of the eight methods of therapy), it cautions further: "It is contraindicated in cases of severe vomiting, severe diarrhea, stranguria [inhibited urination], skin infections, and hemorrhaging; it should be discontinued as soon as the pathogenic factors are dispelled, since excessive sweating may consume yin and yang; the diaphoretic method differs in different seasons, geographic areas, and the conditions of the individual patients. For instance, mild diaphoretics are prescribed in summer, but potent diaphoretics in winter. A large dose of diaphoretic is prescribed for the cold climates, and a smaller dose for the warm climates. Slow-acting diaphoretics are advisable for patients with weak constitutions, and potent ones for patients with strong constitutions...." As the textbook indicates, it is quite important to use diaphoresis properly, especially to avoid harm and to coincide with the conditions of the patient and the environment.
In modern practice, induction of perspiration is frequently overlooked. Acupuncture texts no longer mention it and herb books make only passing reference as necessary to report on traditional categories. Treatment is usually based instead on the practice of treating the symptom complex with matching herbs, but not with matching therapy. Thus, the therapeutic regimen recommended to patients might include herbs for relieving the surface, but sweating is not induced or even monitored.
In some cases, this new approach may still successful; then it would be understandable that further attention to the traditional ideas might not be given. However, if the therapy fails to promptly produce the desired results, one should not necessarily assume first that the wrong herbs were selected. The diaphoretic therapy, not just the surface-relieving herb formulation, might be tried before simply changing to a different set of herbs. Similarly, for those disorders that involve excessive perspiration, specific attempts to inhibit perspiration may be important, beyond simply including a small amount of astringent herbs in the prescription.
Why has diaphoresis been de-emphasized? First, there may have been some failures of diaphoretic therapy due to incorrect application, eventually leading doctors away from the method. During the 18th century Xu Dachun said "Whenever today's physicians apply prescriptions to induce perspiration, they use warm and parching drugs such as magnolia bark, pueraria, chiang-huo, angelica, atractylodes (cangzhu), and tou-kou [a type of cardamon]. If the patient's internal liquids had not yet wasted away, but are heated by the fire of the wind, and if they are then, in addition, parched by the parching herbs, from whence could perspiration develop?" The reference to "fire of the wind" here is to the fact that dryness (as in yin and blood deficiency) leads to internal wind, which stirs up fire that damages the fluids to yield more wind, further vitalizing the fire. Acrid herbs, because of their dispersing nature, also whip up the internal wind (if the essential fluids are insufficient), and they cause further drying, thus stimulating the fire. This is a case of using warming, drying, diaphoretic herbs because the basic therapy is thought to be appropriate for the disease, but making an error in applying it because there are insufficient fluids to support the therapy. If practitioners apply the general rules but fail to make the specific adjustments, they may fail to gain success or, even worse, make their patients suffer additional symptoms. Using a milder treatment as the general approach (leaving out actual diaphoresis) reduces the chance of adverse effects, but might also reduce success in some situations.
Second, the modernization of traditional medicine brings less attention to immediate patient responses (e.g., effects of the first or second herb doses on perspiration) and more to long-term effects (e.g., effects of several days or weeks of treatment on the overall condition of the patient). This is partly because of the high volume of patients who must be seen for a brief time and then seen again some time later, usually when the prescription is deemed, in advance, to need to be checked (e.g., in several days). Also, modern preparation methods steer people away from the high dosage warming decoctions commonly used for diaphoretic therapies, to the lower dosage pills, dried decoctions, and other forms that are less likely to induce perspiration.
Third, the ancient concept that a disease entity could be carried out with the sweat does not match up with modern understanding of disease. Rather, the conception that the person's internal mechanisms (i.e., the immune functions) meet the pathological agent and destroy it, are more prevalent. Even when it is thought that some kind of toxins or other pathological agents need to be expelled from the body, carrying them out via sweat does not play a prominent role in modern thinking about how this could be accomplished. Therefore, it is difficult for practitioners, especially in the West, to request that patients pursue a carefully managed perspiration induction and then give them an acceptable explanation as to why this should be done.
At this time, we do not know the full significance of perspiration in relation to disease state nor the potential benefits (or harm) from inducing perspiration as a therapeutic method. According to traditional doctors, perspiration is quite important. It may not make sense to give out traditional prescriptions (or ones based on them) that were designed for altering perspiration as the means to heal the patient without considering this aspect of the complete treatment. Therefore, one may be cautious about adopting ancient formulas based on ancient indications unless clinical evidence has accumulated to suggest that they still function without what was long considered the correct method of applying them. This same caution would apply not only to diaphoretics, but also to other traditional therapeutic approaches.