Chinese Herbal Medicine (CHM) is a holistic self-contained system of medicine that uses herbs to help attain and maintain human health. Its origins can be traced to the Yellow Emperor’s Inner Classic (黄帝内经, Huang Di Nei Jing) and The Classic of Herbal Medicine (神农本草经, Shen Nong Ben Cao Jing). The system has been evolving through the centuries and keeps showing remarkable results in treating human diseases.
CHM works by utilising the character of the herbs to strengthen the functions of relevant organs, so that the body can fight and overpower the disease more efficiently. CHM looks at the “How?” rather than “What?”, meaning that its focus is on how a disease originates, progresses and can be eliminated, rather than concerning itself with the composition and inner workings of the agents causing the disease. Key theories behind CHM include Yin Yang (阳阴), Five phases (五行), Qi Hua (气化, Qi Transformation), Ba Gua (八卦, especially in the acquired / post-natal 后天 arrangement known as Luo Shu (洛书). CHM looks at each herb as possessing four key qualities (also referred to as code of CHM):
Si Qi - four qualities: a character of the herb (often referred to as temperature) in terms of Yin Yang properties. Although initially recorded to have four qualities - Hot, Warm, Cool and Cold plus Neutral, the scale is now often more granular to include various grades of the initial four qualities, e.g. moderately warm, very cold, and can include seven or nine grades in total. Si Qi is not linked to five elements.
Five Flavours – often referred to as five tastes, reflects medicine’s properties related to five elements. Initially there were five flavours: Sour, Bitter, Sweet, Pungent and Salty; however these have been extended to seven and also include Plain and Astringent, which are similar but not the same as Sweet and Pungent respectively.
Directional intention - includes ascending, descending, floating and sinking. The first two, ascending and descending, are referring to moving up or down the body, the second two, floating and sinking, relate to the depth in the body, floating is moving to the surface and sinking is moving deeper inside the body.
Channel/organ aim – ability of a herb to enter or guide the action to one or more of the Zang Fu organs and their channels, e.g. Kidney, Stomach, etc.
Application of CHM in clinical practice relies on the key theories mentioned above and seeks to target specific part(s) of the body and adjust the function of one or more organs to create a state or environment in the body that is conducive to alleviating current condition and a recovery of a patient from the disease.
For example, Si Qi application is based on the effect of the medicine: hot herbs cinnamon and ginger can help in cold conditions and (cold) watermelon can help with alleviating heat stroke (hot condition).
Si Qi is defined by:
(a) climate (both regional and local, e.g. shady vs sunny side on the same hill will exhibit more Yin and Yang qualities respectively);
(b) shape, colour, taste and texture (e.g. prickly, hard, sharp and pungent represent Yang characteristic, whereas smooth, soft, sweet - Yin);
(c) part of the plant used (flowers and leaves would be more Yang, whereas stem and root will be more Yin), and
(d) preparation method, e.g. fresh, dried, slow cooked and burnt herbs would all have different Si Qi.
Five tastes are applied according to their action on the organs and vital substances:
Sour taste acts on Liver, holds in expanding matter, slows down leakage of Jing and Qi;
Bitter – acts on Heart, detoxifies, dries up the fluids/dampness and is durable;
Sweet – acts on Spleen, tonifies, harmonises formulas, relaxes and slows down energy flow;
Pungent – acts on Lung, expels, invigorates the movement, and also exhausts body fluids;
Salty - acts on Kidneys, moves downward, softens the hardness and connects with blood;
Plain is similar to Sweet, but also acts on Kidneys as well as Spleen, drains the fluids and is diuretic;
Astringent is similar to Sour taste, holds Yin and slows down leakage of Jing.
Directional intention is important to consider in targeting regions of the body, for example, in order to affect upper regions of the body, herbs with ascending properties (e.g. onion) should be used, if lower regions to be targeted, then herbs with descending properties (e.g rhubarb) should be used; if we want the herbs to act on the surface of the body as with skin conditions like acne, then the herbs with floating properties should be used, to affect the body more on a deeper level, herbs exhibiting sinking properties are required.
Other aspects of application of herbs in clinical practice are: using herbs solo or in combination to enhance therapeutic effect and minimise side effects, taking into account herbs’ synergies, toxicity, incompatibility and contraindications, as well as methods of preparation.
Key objectives of herbs preparation are reducing their toxicity as well as enhancing and widening their effect. For example, using salt will help with enhancing treatment of Kidneys, vinegar - Liver, using yellow soil will settle the Spleen, honey - will tonify and moisten, frying or roasting will create more heat.
An important principle of “Monarch-Minister-Assitant-Guide” (Jun-Chen-Zuo-Shi) is used in building formulas when multiple ingredients and multiple targets are required. Monarch (Sovereign) herb plays principal role in treatment, Minister herb supports the Monarch by doing a lot of work, Assistant is helping both Monarch and Minister and may be used to enhance therapeutic effect or inhibit their toxicity; Guiding herb is used to guide therapeutic effects of main herbs in the formula to the relevant organs, channels or parts of the body.