The Principle‑Method‑Formula‑Medicinal Therapeutic System of Traditional Chinese Medicine

The Principle‑Method‑Formula‑Medicinal Therapeutic System of Traditional Chinese Medicine
In disease treatment, Traditional Chinese Medicine (TCM) adheres to the step‑by‑step logic of Principle, Method, Formula, Medicinal.
At the highest level, the principle can be briefly stated as reducing excess and supplementing deficiency, which restores the organism from pathological states of excess or deficiency back to balance. As mentioned above, this balanced state is encapsulated in the TCM tenet: When yin is stable and yang is secure, vitality remains well‑regulated. It bears a high degree of similarity to the concept of homeostasis in Western medicine.
The TCM concept of method consists of two dimensions. The first dimension refers to therapeutic principles, the over‑arching guidelines for treatment. The second denotes therapeutic approaches, namely concrete intervention strategies formulated in compliance with therapeutic principles.
The therapeutic principles of TCM embody the philosophy of neutralization, analogous to acid‑base neutralization in chemistry. The chapter Treatise on the Essential Truth (Zhi Zhen Yao Da Lun) in The Yellow Emperor’s Inner Classic summarizes these principles in the following passage:
"Treat all instances of preponderance and counteraction: treat cold patterns with heat, heat patterns with cold, warm conditions with cooling therapy, cool conditions with warming therapy, dispersing patterns with astringents, stagnant patterns with dispersants, dryness with moistening, tension with relaxation, hardness with softening, fragility with consolidation, debilitation with tonification, and excess with purgation. Bring each type of qi to a state of clarity and tranquility, so that pathogenic qi subsides and returns to its origin. This constitutes the general framework of treatment."
Based on these core therapeutic principles, TCM physicians of successive dynasties have summarized and classified clinical therapeutic methods to facilitate learning for later generations.
The most classic classification is the Eight Therapeutic Methods: sweating, harmonizing, purgation, resolution, emesis, heat‑clearing, warming, and tonification. This system, known as the Eight Methods of Medicine, was systematically established by Cheng Guopeng, a physician of the Qing Dynasty. He categorized disease pathomechanisms under the Eight Principles: yin, yang, exterior, interior, deficiency, excess, cold and heat, and developed corresponding neutralizing therapeutic interventions for each pathomechanism. Thanks to its clear and accessible theoretical framework, this doctrine has been widely accepted in modern‑day TCM.
Despite proposing the Eight Methods of Medicine, Cheng Guopeng did not reduce TCM therapeutics rigidly to these eight modalities; instead, he advocated flexible clinical application. A single formula may integrate multiple methods, for example, harmonization, tonification and resolution can be applied simultaneously. He also argued that one therapeutic method may transform into another, stressing that treatment strategies must adjust dynamically to clinical circumstances.
Sweating method (exterior‑releasing method) induces perspiration, so that pathogenic factors invading the body are expelled together with sweat. It is primarily indicated for various exterior syndromes, and relieves aversion to cold, fever, headache, generalized body pain, nasal congestion and rhinorrhea.
Harmonizing method (mediation method) eliminates pathogens and regulates visceral functions through mediation and harmonization. Its defining characteristics are combined use of cold‑ and warm‑natured medicinals, concurrent tonification and purgation, and simultaneous resolution of exterior and interior disorders. Harmonizing formulas represent the largest subgroup within the TCM formulary, and this method is commonly adopted for complex diseases.
Purgation method expels food residues, retained fluid, static blood, phlegm accumulation and other metabolic waste that the body cannot normally excrete. It usually employs purgatives, blood‑activating stasis‑resolving agents or diuretics, and falls under drastic purgative therapy in TCM.
Resolution method covers digestion, dissipation and elimination. Although it targets pathological products similar to those addressed by purgation, its intervention mode differs. It gradually dissolves food stagnation, qi stagnation, static blood and phlegm accumulation via medicinals, and acts on pathogens deeply lodged in zang‑fu organs that cannot be readily eliminated through simple purgation.
Emesis method induces vomiting with medicinals or physical maneuvers, expelling pathogens stagnating in the throat, chest‑diaphragm and gastric cavity to alleviate symptoms. This intervention is also used in Western medicine for certain poisoning cases.
Heat‑clearing method eliminates warm‑heat and toxic pathogens via heat‑clearing, fire‑draining, detoxifying and blood‑cooling effects. The contemporary TCM therapeutic principle of clearing heat and detoxifying belongs to this category.
Warming interior method dispels interior‑cold syndromes by warming the interior, expelling cold, recuperating yang and unblocking meridians. In modern clinical practice, it is also called yang‑supporting therapy, whose main indications include cold extremities, cold aversion, pale complexion, non‑dry mouth and white tongue coating.
Tonification method remedies deficiency of yin, yang, qi and blood, and is indicated for deficiency syndromes caused by various forms of insufficiency.
Building upon the above‑mentioned theories, contemporary monographs on TCM formulas further classify prescriptions into twenty categories: exterior‑releasing formulas, purgative formulas, harmonizing formulas, heat‑clearing formulas, summerheat‑dispelling formulas, interior‑warming formulas, dual exterior‑interior resolving formulas, tonifying formulas, astringent formulas, spirit‑calming formulas, orifice‑opening formulas, qi‑regulating formulas, blood‑regulating formulas, wind‑treating formulas, dryness‑moistening formulas, dampness‑eliminating formulas, phlegm‑dispelling formulas, digestion‑promoting formulas, anthelmintic formulas, and emetic formulas, in order to facilitate learning and mastery.
Nevertheless, a school in TCM known as the Classical‑Formula (Jing‑Fang) School disagrees with this classification. Its proponents oppose rigid categorization of formulas. They advocate respecting medical heritage, especially the classics compiled during the Han and Tang dynasties, with priority given to Treatise on Cold‑Damage Diseases and Essential Prescriptions from the Golden Cabinet written by Zhang Zhongjing of the Han Dynasty, and propose studying formula applications according to their specific indications.
Guizhi Tang (Cinnamon Twig Decoction), the inaugural formula recorded in Treatise on Cold‑Damage Diseases, is a well‑known classical prescription. Its corresponding textual record reads:
"Taiyang wind‑stroke pattern: yang floats outward while yin is weakened internally. Yang floating leads to spontaneous fever, while yin debilitation brings on spontaneous sweating. The patient suffers from shivering aversion to cold, subtle wind‑aversion, mild steaming fever, nasal snoring and dry retching. Guizhi Tang governs this condition.
Guizhi Tang Formula
Ramulus Cinnamomi 3 liang (peeled), Radix Paeoniae 3 liang, Radix Glycyrrhizae 2 liang (honey‑fried), Rhizoma Zingiberis Recens 3 liang (sliced), Fructus Jujubae 12 pieces (broken open).
Crush the five ingredients (three medicinals are to be cut and pounded). Add 7 sheng of water, simmer over mild heat until 3 sheng of decoction remains, strain off the residue, adjust the temperature and take 1 sheng of the liquid. Shortly after administration, drink over 1 sheng of warm thin congee to potentiate the medicinal effect. Keep the patient warmly covered for about one hour; fine, gentle, all‑over perspiration is optimal. Copious, streaming sweat will fail to cure the disease.
If sweating resolves symptoms after the first dose, discontinue subsequent medication and there is no need to finish the whole decoction. If no sweating occurs, repeat the dose following the same procedure. If perspiration is still absent, shorten the dosing interval and complete three doses within roughly half a day. Severe cases may receive medication day and night with round‑the‑clock observation. If symptoms persist after one full dose, repeat the prescription; if sweating still cannot be induced, administer up to two or three doses.
Avoid raw‑cold, sticky‑slippery foods, meat and wheat products, five pungent herbs, fermented dairy products and malodorous foods."
This passage specifies the cardinal symptoms treated by Guizhi Tang: spontaneous sweating, cold aversion, wind aversion, fever, nasal snoring and dry retching. It also elaborates in detail on decocting methods, administration protocols and dietary restrictions. The Classical‑Formula School strictly follows the principle: administer the corresponding formula (or medicinal) for the corresponding pattern.
This rigorous mindset of the Classical‑Formula School fits clinical practice well. Its drawback, however, lies in a certain degree of one‑sidedness: it overstates the primacy of Treatise on Cold‑Damage Diseases and Essential Prescriptions from the Golden Cabinet, and holds that nearly all diseases can be treated with classical formulas. Gradually, a clinically practical therapeutic thinking degenerates into dogmatism, thus drifting away from real‑world clinical realities.
In fact, most patients with chronic conditions present highly complex symptom clusters. Diseases do not develop strictly in accordance with textbook descriptions, and clinicians cannot mechanically apply classical formulas in a cookbook‑like manner.
I personally incline toward the more moderate Formula‑Pattern (Fang‑Zheng) School. This school also abides by the rule "prescribe the corresponding formula (or medicinal) for the presenting pattern", yet draws prescriptions from a much broader scope. Clinically effective formulas from all dynasties, as well as evidence‑verified modern prescriptions and medicinals screened through controlled trials, can all be incorporated into the formula‑pattern system.
Meanwhile, I do not reject the Eight Therapeutic Methods or modern TCM formula classifications, for these systems are also built on clinical efficacy.
Ultimately, regardless of TCM schools, the fundamental therapeutic principle remains reducing excess and supplementing deficiency, that is, regulating pathological excess and deficiency states of the human body.
Once the principle and method are established, clinicians’ formula‑construction logic is determined. The next step involves formula and medicinal selection, whose primary criterion is whether the chosen prescriptions and medicinals can relieve the patient’s symptoms. This process severely tests a physician’s foundational expertise. The author holds that the most solid foundational skill for TCM practitioners is memorizing the indications of formulas and single medicinals, which is the core guarantee of clinically effective prescriptions.