One general therapeutic strategy in traditional Chinese medicine is to replenish deficiencies and remove excesses of yin or yang. This focuses on holistic regulation in the body and employs an important concept: dual modulation. This generally refers to both the body or herb’s abilities to regulate a specific physiological function. There are many examples of how this works in herbal medicine, which has unique theories about the categorisation and regulating properties of medicinal substances. There are eight actions or effects that a particular herb might be classified. These are its properties of ascending and descending, cold and heat production, yin and yang, reinforcement and reduction, excretion/draining and astringent (holding on) effect, dryness and moisture, activating and stopping or slowing down circulation, and dissolving and gathering. A herb’s underlying action can sometimes be changed just by manipulating its dosage, the processing and preparation methods or what else it may be combined with. A single herb usually contains multiple active ingredients that can have opposite effects on the body. For example, notoginseng is used to stop bleeding and promote blood flow. Pharmacological research has shown that the herb dually modulates blood clotting. Its active ingredient – saponin – activates blood circulation and dissolves blood stasis, whereas another active ingredient – dencichine – stops bleeding. TCM physicians know that certain herbs in different doses will produce different and often opposite health effects. For example, astragalus (right) is a good herb for chi deficiency. For low blood pressure due to chi deficiency, astragalus can be used in large amounts (about 30g) to lower the blood pressure, Astragalus can wither increase or decrease blood pressure, depending on the amount used. Bu understanding dual modulation effects, it’s clear why there’s such variety in the efficacies of products that contain the same herbs. All the above interactions contribute to make a unique product that can have completely different effects from a similar formula if any of these factors are altered, Furthermore, these formulas may react differently from person to person, depending on their body constitution or if they’re sick or well, this is another important aspect of dual modulation often overlooked. Before taking any medicine, consult your TCM or medical practitioner Rose Tse and Angela Collingwood info@shen-nong.com Edited by Suzanne Harrison suzanne.harrison@scmp.com Published: September 12, 2005 Source: South China Morning Post