The Eight Principles of Differentiation (Ba Gang Bian Zheng) refer to the eight categories of syndromes in Traditional Chinese Medicine (TCM): Yin and Yang, Deficiency and Excess, Exterior and Interior, Cold and Heat. This is the fundamental framework for syndrome differentiation in TCM. As the saying goes, “To treat diseases, one must understand the eight principles: Yin, Yang, Deficiency, Excess, Exterior, Interior, Cold, and Heat. If these principles are not distinguished, it can lead to fatal consequences.” Yin and Yang serve as the overarching principles that encompass the other six aspects, where Exterior, Heat, and Excess are associated with Yang, while Interior, Cold, and Deficiency are associated with Yin. The key points of the Eight Principles of Differentiation are thus referred to as “Two Principles and Six Essentials.”
Yin Syndrome: Any illness that is located in the Interior, in the blood, is categorized as Deficiency, Cold, and is characterized by insufficient Zheng Qi (Vital Energy), with the body’s response often showing signs of decline, falls under the category of Yin Syndrome. The etiology and pathogenesis include aging, weakness, prolonged illness, or the invasion of external pathogens into the internal organs, leading to weakened Zheng Qi and an excess of Yin. Yang Syndrome: Any illness that is located in the Exterior, in Qi, is categorized as Excess, Heat, and the Zheng Qi is not harmed, with the body’s response often showing signs of excess, falls under the category of Yang Syndrome. The etiology and pathogenesis include the invasion of pathogenic Qi, where the pathogenic factor is strong and Zheng Qi is also strong, leading to a conflict between Zheng and Xie (Pathogenic) Qi resulting in Yin Deficiency and Yang Excess.
TCM theory states, “Yin and Yang are mutually rooted; Yin is the root of Yang, and Yang is the foundation of Yin.” “To effectively tonify Yang, one must seek Yang within Yin, allowing Yang to be nourished by Yin for boundless transformation; to effectively tonify Yin, one must seek Yin within Yang, allowing Yin to be elevated by Yang.” This means that Yin and Yang are not only oppositional but also unified, existing within a defined framework while being capable of transformation.
Yin Syndrome (Yang Deficiency) typically presents with symptoms such as aversion to cold, lack of thirst, weak voice, loose stools, clear and frequent urination, pale tongue with white coating, and thin, weak pulse. In contrast, Yang Syndrome (Yin Deficiency) typically presents with symptoms such as heat in the palms and soles, dry mouth and throat, loud voice, constipation, short and red urination, red tongue with yellow coating, and a large, rapid pulse.
Both Yin and Yang Deficiency indicate the presence of both Yin and Yang Deficiencies, primarily characterized by aversion to both cold and heat, with a particular aversion to cold in winter and to heat in summer. This reflects a state of imbalance or dual deficiency of Yin and Yang. The etiology and pathogenesis include five aspects: weak constitution, excessive fatigue, irregular diet, prolonged illness, and misdiagnosis or mistreatment.
Treatment for Yin Deficiency should focus on nourishing Yin fluids, while Yang Deficiency should be treated with warming tonics for Kidney Yang. For both Yin and Yang Deficiency, a combined approach of nourishing both Yin and Yang is recommended, such as nourishing Yin and warming Yang, and tonifying Yin while strengthening Yang, with attention to first regulating the Spleen and Stomach if they are weak.
Individuals with a Yin Deficiency constitution should focus on nourishing Yin fluids and may add a small amount of Yang tonics. Foods that nourish Kidney Yin include wheat, millet, black sesame, glutinous rice, mung beans, tofu, lily bulbs, black fungus, white fungus, tomatoes, spinach, papaya, honey, water chestnuts, figs, pomegranates, apples, pears, mulberries, peaches, sugarcane, and rock candy. Meats and eggs should include pork, pig skin, duck, soft-shelled turtle, black fish, squid, turtle, crab, jellyfish, sea cucumber, and oysters, which are all cold in nature and have nourishing Yin properties. Herbal medicines that nourish Yin and clear heat include Nu Zhen Zi (Ligustrum fruit), Shan Zhu Yu (Cornus fruit), Wu Wei Zi (Schisandra fruit), Han Lian Cao (Eclipta), Sha Shen (Glehnia), Tian Dong (Asparagus), Mai Dong (Ophiopogon), Shi Hu (Dendrobium), Yu Zhu (Polygonatum), and Gou Qi Zi (Goji berry). Individuals with Yin Deficiency and excess heat should avoid spicy and warming foods such as Sichuan pepper, chili, fennel, scallions, ginger, leeks, longan, lychee, walnuts, dog meat, and lamb; alcohol, coffee, and strong tea should also be avoided. During exercise, one should control sweating, as excessive sweating can deplete Yin fluids. Maintaining adequate sleep and a positive emotional state is essential for nourishing Yin Qi.
Individuals with a Yang Deficiency constitution should consume more Yang-supporting foods, such as lamb, beef, dog meat, venison, hairtail fish, sparrow meat, chicken, yellow eel, pig stomach, shrimp, grass carp, ginger, scallions, garlic, leeks, okra, mustard seeds, pepper, fennel, longan, lychee, lotus seeds, chestnuts, and walnuts. Herbal medicines that warm and tonify the Kidney and Liver include Lu Rong (Deer Antler), Yin Yang Huo (Epimedium), Hai Gou Shen (Sea Dog Kidney), Ge Jie (Gecko), Dong Chong Xia Cao (Cordyceps), Ba Ji Tian (Morinda), Gou Qi Zi (Goji berry), Rou Cong Rong (Cistanche), Yi Zhi Ren (Alpinia), Tu Si Zi (Cuscuta), Du Zhong (Eucommia), Zi He Che (Placenta), and Sha Yuan Zi (Astragalus). It is important to limit the intake of raw or cold foods such as watermelon, bitter melon, winter melon, water spinach, Chinese cabbage, bamboo shoots, kelp, mung beans, seaweed, pears, and sugarcane. In autumn and winter, appropriate warm clothing should be worn, and staying up late should be avoided, with warm foods to nourish Yang Qi. In summer, one should avoid intense exercise to prevent excessive sweating, which can harm Yang, and should not indulge in cold drinks.
The selection of Chinese patent medicines should also be based on syndrome differentiation. For early-stage hypertension, the primary syndrome is often Yin Deficiency with Yang Excess (red tongue and irritability), so Jin Gui Shen Qi Wan (Kidney Qi Pill) should not be taken; in later stages, some may present with Yang Deficiency (aversion to cold), thus Qi Ju Di Huang Wan (Lycium and Chrysanthemum Pill) is not suitable. For coronary heart disease, the main syndrome is chest Yang not thriving, and aromatic, Yang-opening, and orifice-opening medicines like Guan Xin Su He Wan (Heart Rescue Pill) are excellent for heart protection, but are not suitable for those with Yin and Kidney Deficiency (red tongue and little fluid).
For those with Kidney Yin Deficiency and mild heat, Liu Wei Di Huang Wan (Six Flavor Rehmannia Pill) can be selected; for those with Yin Deficiency and excess heat, Zhi Bai Di Huang Wan (Anemarrhena and Rehmannia Pill) or Da Bu Yin Wan (Great Tonifying Yin Pill) can be chosen. For oral ulcers caused by Yin Deficiency and excess heat, Kou Yan Qing Granules can be selected; for those with Kidney Yin Deficiency and Blood Deficiency, Gui Shao Di Huang Wan (Gui and Peony Pill) is appropriate; for those with Liver and Kidney Yin Deficiency accompanied by dizziness, blurred vision, or reduced eyesight, Qi Ju Di Huang Wan (Lycium and Chrysanthemum Pill) or Ming Mu Di Huang Wan (Vision Brightening Rehmannia Pill) can be selected; for those with severe Kidney Yin Deficiency without internal heat symptoms, Zuo Gui Wan (Left Return Pill) is suitable; for elderly individuals with Kidney Deficiency-related tinnitus or deafness, Er Long Zuo Ci Wan (Ear Tinnitus Pill) can be selected; for cough and asthma due to Lung and Kidney Yin Deficiency, Mai Wei Di Huang Wan (Ophiopogon and Rehmannia Pill) or Bai He Gu Jin Wan (Lily and Rehmannia Pill) can be chosen; for those with severe Lung and Kidney Yin Deficiency and significant Qi depletion, He Che Da Zao Wan (Placenta Great Nourishing Pill) is appropriate; for those with Qi and Yin Deficiency, palpitations, and shortness of breath, Sheng Mai Yin (Generate Pulse Decoction) is suitable; for those with Heart Yin Deficiency, insomnia, and vivid dreams, Tian Wang Bu Xin Wan (Heavenly Emperor Heart Tonifying Pill) can be selected.
For individuals with Kidney Yang Deficiency, suitable Chinese patent medicines include Jin Gui Shen Qi Wan (Kidney Qi Pill), Gui Fu Di Huang Wan (Cinnamon and Rehmannia Pill), Si Shen Wan (Four Spirit Pill), You Gui Wan (Right Return Pill), Ji Sheng Shen Qi Wan (Kidney Qi Pill), and Suo Yang Gu Jing Wan (Lock Yang and Secure Essence Pill). For Spleen Yang Deficiency, suitable Chinese patent medicines include Fu Zi Li Zhong Wan (Aconite and Middle-Strengthening Pill) and Gui Fu Li Zhong Wan (Cinnamon and Middle-Strengthening Pill). For Stomach Yang Deficiency, suitable Chinese patent medicines include Xiang Sha Yang Wei Wan (Aromatic and Stomach Nourishing Pill), Xiao Jian Zhong Granules (Minor Constructing Middle Granules), Si Ni Tang (Four Reversal Decoction), and An Zhong Pian (Calm Middle Tablets). For Heart Yang Deficiency, suitable Chinese patent medicines include Shen Fu Qiang Xin Wan (Ginseng and Aconite Heart Strengthening Pill) and Qi Li Qiang Xin Jiao Nang (Qi Li Heart Strengthening Capsules). For Liver Yang Deficiency, suitable Chinese patent medicines include Shi Xiang Wan (Ten Fragrance Pill) and Huo Xiang Ju He Wan (Agastache and Tangerine Seed Pill).
Both Yin and Yang Deficiency can lead to disease due to deficiency, or can cause fatigue due to illness; or can lead to deficiency due to prolonged illness, or can cause Yin Deficiency to affect Yang over time, or Yang Deficiency to affect Yin, resulting in both Yin and Yang Deficiency. The condition is often complex and is best treated with herbal decoctions based on syndrome differentiation. Chinese patent medicines that tonify both Yin and Yang, such as Bu Shen Yi Nao Pian (Kidney and Brain Nourishing Tablets), Gui Qi Shen Oral Liquid (Tortoise and Qi Nourishing Oral Liquid), Shen Rong Wei Sheng Wan (Ginseng and Deer Antler Health Preservation Pill), and Shen Rong Yan Ling Pian (Ginseng and Deer Antler Longevity Tablets) have the function of tonifying Qi, Blood, Yin, and Yang.
In summary, according to TCM treatment principles, heat should be treated with cold, cold with heat; excess should be drained, deficiency should be tonified; fatigue should be rested, and rest should be active, achieving balance and harmony, and maintaining equilibrium between Yin and Yang.
Note: Some text and image resources in this article are sourced from the internet. The purpose of reprinting this article is to convey more information. If there are any errors in source attribution or infringement of your legal rights, please notify us immediately, and we will delete it promptly and apologize to you.
Previous Highlights:
8 Chinese Patent Medicines for Acne. Recommended for Collection.
Who Should Absolutely Avoid Sildenafil? How to Use It Safely?
Seven Chinese Patent Medicines for Constipation! Recommended for Collection.