With a history of 2000 to 3000 years, Traditional Chinese Medicine (TCM) has formed a unique system to diagnose and cure illness. The TCM approach is fundamentally different from that of Western medicine. In TCM, the understanding of the human body is based on the holistic understanding of the universe as described in Daoism, and the treatment of illness is based primarily on the diagnosis and differentiation of syndromes.
Together with acupuncture, herbal medicine is a major pillar of Chinese medicine. The Chinese pharmacopoeia lists over 6,000 different medicinal substances in terms of their properties and the disharmonies that they were helpful with. There are about 600 different herbs in common use today.
Herbs are classified in two major dimensions. The first dimension refers to the temperature characteristics of the herb, namely hot (re), warm (wen), cold (han), neutral (ping), and aromatic. The second dimension refers to the taste property of the herb, namely sour (suan), bitter (ku), sweet (gan), spicy (xin), and salty (xian).
The various combinations of temperature and taste give the herb its properties that can influence the yin and yang energy patterns of the body. For example, sour, bitter and salty tastes are related to yin, whereas acrid, sweet are attributed to yang. There are herbs that will warm, herbs that will cool, herbs that will tonify, herbs that will move stagnation and so on. It is also important to understand that herbs do not possess one quality. They are most always a combination of properties and temperatures and may reach one to as many as twelve organ systems. Warm herbs can be used with individuals suffering from Heat disorders, but the herb with warm energy must be mixed with herbs with Cool/Cold energy so that the overall balance of the mixture is on the Cool side. Likewise, Cool herbs can be used with people with Cold disorders as long as the overall balance of the mixture is warm. Neutral herbs are those that are neither hot nor cold, so they are often considered gentle herbs. There are not too many neutral herbs in the pharmacopoeia.
As for the tastes, sour constricts or consolidates. Herbs of sour taste are often indicated for use in perspiration due to deficiency, protracted cough, chronic diarrhea, seminal and urinary incontinences, leakage or spermatic fluid, and other conditions related to hypo-metabolism (under-performance). In traditional Chinese medicine, they are seen as deficient or cold patterns.
Bitter possesses the function of clearing heat, purging the bowels, lowering the qi, improving appetite and drying dampness or wetness. Bitter herbs are commonly used in fire-heat patterns, such as the acute stage of infectious disease, and the patterns of damp-heat or damp-cold, such as in arthritis or leucorrhoea.
Sweet has the function of toning, improving, moistening and harmonizing many of the important systems of the body, including the digestive, respiratory, immune and endocrine systems. Sweet tastes also relieve urgency and inhibit pain due to the constrictive action of muscles. They are commonly used for treating deficiency patterns such as dry cough, and dysfunction of the gastro-intestinal tract such as spleen and stomach disharmony.
Spicy disperses, circulates qi and vitalizes blood. This group of herbs can stimulate the sweat glands to perspire, circulate qi, activate the function of meridians and organs and vitalize blood to promote blood circulation. As a whole, spicy herbs have the overall effect of activating and enhancing metabolism. Spicy herbs are commonly used in the treatment of external patterns (catching a cold), when the function of the meridian and organs is weakened and circulation of blood has been impeded. In traditional Chinese medical terminology, this is the stage of qi stagnation and blood cloudiness.
Salty herbs have the function of softening firm masses and fibrous adhesions. The salty taste purges and opens the bowels. Salty agents are often indicated in sores, inflammatory masses, cysts, and connective tissue proliferation.
The unique characteristic of Chinese herbal medicine is the degree to which formulation is done. In other forms of herbal medicine, especially western herbal medicine, herbs are often delivered singly or combined into very small formulas of herbs with the same function. In contrast, Chinese herbalists rarely prescribe a single herb to treat a condition. They create formulas instead. A formula usually contains at least four to twenty herbs.
Herbal formulas can be delivered in all manners of preparation. Pre-made formulas are available as pills, tablets, capsules, powders, alcohol-extracts, water-extracts, etc. Most of these formulas are very convenient as they do not necessitate patient preparation and are easily taken. However, the concentration of the herbs in these products is low and don't allow the practitioner to adjust the contents or dosages. These products are usually not as potent as the traditional preparation of decoction.
Decoction is the traditional method of preparing herbal medicine. A decoction is a concentrated form of tea. The practitioner weighs out a day's dosage of each herb and combines them in a bag. A patient is given a bag for each day the herbal formula will be taken. The herbs are then boiled in water by the patient at home. The boiling process takes from 30-60 minutes and the resulting decoction will be consumed several times during the day.
Another modern way of delivering herbs is through granulated herbs, which are highly concentrated powdered extracts. These powders are made by first preparing the herbs as a traditional decoction. The decoction is then dehydrated to leave a powder residue. Practitioners can then mix these powders together for each patient into a custom formula. The powder is then placed in hot water to recreate the decoction. This eliminates the need to prepare the herbs at home, but still retains much of the original decoction's potency.