hinese herbs are commonly used in a combination of two or more herbs, called a formula, to increase or to reinforce the effects of each medicinal substance, to minimize toxicity or side effects, to accommodate complex clinical situations, and to alter the actions of the substances. Although the principles of combining herbs are usually introduced in a prescription manual, not in a materia medica, it is necessary to understand how and why the herbs are combined as well as some general rules for combining herbs including the compatibility, contraindication, and dosage.
Classical formulas were developed from long-term clinical experience. The combined application of the herbs in a formula follows some general rules, such as the Seven Features, which illustrate the relationship between combined herbs:
mutual accentuation (xiang xu, literally means " mutual necessity") Mutual accentuation refers to the combination of two substances with similar function, which can achieve remarkable reinforced synergistic effects. For example, the combination of Gypsum (Shi Gao) and Rhi-zoma Anemarrhenae Asphodeloidis (Zhi Mu) reinforces the effect of clearing Heat and draining Fire, and the combination of Rhizoma Rhei (Da Huang) and Mirabilitum (Mang Xiao) reinforces the effect of purging the Intestines.
mutual enhancement (xiang shi, literally means " mutual employment") Mutual enhancement refers to the combination of two or more substances similar in certain aspects of their characteristics and functions in which one of the substances enhances the effect of the other in a specific clinical situation. For example, when Sclerotium Poriac Cocos (Fu Ling) is combined with Radix Astragali Membranacei (Huang Qi), the former can enhance the effect of Radix Astragali Membranacei (Huang Qi), which tonifies Qi and generates Water excretion. When Radix Scutellariae Baicalensis (Huang Qin) is combined with Radix et Rhizoma Rhei (Da Huang), Radix et Rhizoma Rhei (Da Huang) enhances the effect of clearing Heat and purging Fire.
mutual counteraction (xiang wei, literally means " mutual fear") Mutual counteraction refers to the combination in which the toxicity and side effects of one substance are reduced or eliminated by the another substance. For example, the toxicity and side effects of Rhizoma Pinel-liae (Ban Xia) and Arisaema Cum Bile (Dan Nan Xing) can be reduced by combination with Rhizoma Zingiberis Recens (Sheng Jiang).
mutual suppression (xiang sha, literally means " mutual killing") Mutual suppression is the reverse of mutual counteraction. In this case, the emphasis is on the substance that performs the action. For example, Rhizoma Zingiberis Recens (Sheng Jiang) reduces the toxicity and side effects of Rhizoma Pinelliae (Ban Xia) and Arisaema Cum Bile (Dan Nan Xing).
mutual antagonism (xiang wu, literally means " mutual aversion") Mutual antagonism refers to the combination in which the primary effect of one substance is reduced or eliminated by the other substance. For example, Semen Raphani (Lai Fu Zi) antagonizes Radix Ginseng (Ren Shen) because the former weakens the function of tonifying Qi by Radix Ginseng (Ren Shen).
mutual incompatibility (xiang fan, literally means " mutual opposition") Mutual incompatibility refers to the combination of two substances that causes toxic or adverse side effects. For example, there are eighteen incompatible medicaments that are believed to give rise to serious side effects, if given in combination.
single effect (dan xing, literally means " single going")
Single effect refers to a single substance that is used to achieve the desired therapeutic effects without any accessory substances. Decoction of Radix Ginseng (Ren Shen) is an example.
In short, a combination leading to an increase of the therapeutic effects of any and all herbs should be used clinically. A combination of herbs counteractive to each other and which reduces primary effects should be used care fully. A combination of herbs that can reduce or eliminate toxicity or that reduces adverse side effects, must be considered when using toxic substances. A combination that causes toxicity or strong adverse side effects should be avoided at all times.
Traditional Chinese herbs are very safe in general, but they can be harmful to the body if used improperly. There are four types of contraindications or prohibitions in using these substances.
contraindication to the symptoms Contraindication to the symptoms refers to the use of an herb for diseases or symptoms inappropriate to the indications of the herb. For example, Herba Ephedrae (Ma Huang) has the function of inducing diaphoresis and relieving asthma. Its indications include invasion of Wind-Cold, exterior and excess symptoms, and cough due to obstruction of the Lung-Qi. Thus, for patients with spontaneous sweating due to Qi deficiency or cough due to the Lung deficiency, Herba Ephedrae (Ma Huang) is prohibited.
incompatibility of substances Incompatibility of substances refers to the combinations of herbs that should not be used simultaneously. These combinations may reduce the therapeutic effects of the herbs or lead to toxic-ity or side effects. Ancient medical literature summarized the incompatibility into two lists called the Eighteen Incompatible Medications (Shi Ba Fan) and the Nineteen Medications of Mutual Antagonism (Shi Jiu Wei). Modern research has shown that some of these are incorrect.
Eighteen Incompatible Medications (Shi Ba Fan)
• Radix Glycyrrhizae (Gan Cao) is incompatible with Radix Kansui (Gan Sui)
Radix Knoxiae (Da Ji) Sargassum (Hai Zao) Flos Genkwa (Yuan Hua)
• Radix Aconiti (Wu Tou) is incompatible with Bulbus Fritillariae Cirrhosae (Bei Mu) Fructus Trichosanthis (Gua Lou)
Rhizoma Pinelliae (Ban Xia)
Radix Ampelopsis (Bai Lian)
Rhizoma Bletillae (Bai Ji)
Radix Veratri (Li Lu)
Radix Ginseng (Ren Shen)
Radix Adenophorae seu Glehniae (Sha Shen)
Radix Salviae Miltiorrhizae (Dan Shen)
Radix Scrophulariae (Xuan Shen)
Herba Asari ( Xi Xin)
Radix Paeoniae Lactiflorae (Bai Shao)
Nineteen Medications of Mutual Antagonism
• Sulfur (Liu Huang) antagonizes Sal Glauberis (Pu Xiao)
• Hydrargyrum (Shui Yin) antagonizes Arsenicum (Pi Shuang)
• Radix Euphorbiae Fischerianae (Lang Du) antagonizes Lithargyrum (Mi Tuo Seng)
• Fructus Crotonis (Ba Dou) antagonizes Semen Pharbitidis (Qian Niu Zi)
• Flos Caryophylli (Ding Xiang) antagonizes Radix Curcumae (Yu Jin)
• Radix Aconiti (Wu Tou) antagonizes Cornu Rhinocerotis (Xi Jiao)
• Cortex Cinnamomi Cassiae (Rou Gui) antagonizes Halloysirum Rubrum (Chi Shi Zhi)
• Radix Ginseng (Ren Shen) antagonizes Faeces Trogopterorum (Wu Ling Zhi)
contraindication during pregnancy Some herbal substances may have side effects that may injure the fetus or induce miscarriage. These substances are divided into two groups: contraindication and caution. Contra-indicated substances are toxic or extremely harsh toward pregnancy such as Fructus Crotonis (Ba Dou), Semen Pharbitidis (Qian Niu Zi), Radix Knoxiae (Da Ji), Mylabris (Ban Mao), Radix Phytolaccae (Shang Lu), Moschus (She Xiang), Rhizoma Spargani (San Leng), Rhizoma Curcumae (E Zhu), and Hi-rudo (Shui Zhi). This group of substances should never be used during pregnancy. Substances in the second group are those with the function of invigorating Blood and removing Blood Stasis, such as Semen Persicae (Tao Ren), Flos Carthami (Hong Hua), Radix Et Rhizoma Rhei (Da Huang), Fructus Aurantii Immaturus (Zhi Shi), Radix Aconiti Lateralis Preparata (Fu Zi), Rhizoma Zingiberis (Gan Jiang), and Cortex Cinnamomi (Rou Gui). These substances should be used with extreme care.
dietary incompatibility Diet is considered an important influence on health and illness in TCM. Food items, such as meat, vegetables, and various seasonings, all have their own properties and flavors, just as herbal substances do. Thus, everyday food intake may conflict with the herbs a patient takes. In general, when Chinese herbs are used, certain kinds of food—raw, cold, greasy, or other relatively hard-to-digest foods—should be avoided. Or, according to the condition of the disease, some food should not be eaten at all. For example, for patients with Cold symptoms, uncooked or cold food should be avoided. For patients with Heat symptoms, greasy foods or oils of any kind should be avoided. For patients with dizziness, insomnia, and impetuous temperament, pepper, hot pepper, wine, garlic, and other spices should be avoided. For patients with indigestion due to Spleen and Stomach Deficiency, fried, greasy, and sticky food should be avoided. For patients with infections on their body surface and cutaneous pruritus, fish, shrimps, crabs, and other seafood should be avoided.
According to traditional theory, some food types should be avoided when taking certain medicinal substances. For example, patients taking Radix Reh-manniae Glutinosae (Sheng Di Huang), Radix Rehmanniae Glutinosae Con-quitae (Shu Di Huang), and Radix Polygoni Multiflori (He Shou Wu) should avoid onion, garlic, and radish; patients taking Sclerotium Poriae Cocos (Fu Ling) should avoid onion; patients taking Herba Menthae (Bo He) should avoid turtle flesh; patients taking Fructus Quisqualis (Shi Jun Zi) and Rhi-zoma Smilacis Glabrae (Tu Fu Ling) should avoid tea.
dosage Dosage refers to the amount of an herb used in a prescription or the daily amount of the herb suitable for an adult. Dosage is a topic of extreme importance in composing a prescription. It is with dosage that specific aspects of a therapeutic strategy can be emphasized or de-emphasized. Traditional practitioners believed that the variables governing the dosage of a particular substance (e.g., clinical presentation, duration of disease, and strength of the herb) were too complex to establish a general standard. However, there are still some common rules for people to follow. The common dosage for most of the available substances is I— 3 qian or 3 —10 grams. (For conversion between qian and gram, see below.) Exceptions to this depend on a few variables, such as the property of the substance, preparation method, the role of the substance in a formula, severity of the disease, and condition of the patient.
Dosage of drastic or toxic substances starts in small amounts. As soon as the condition of the patient improves, the dosage should be reduced or the herb should be discontinued to avoid poisoning. Hard and heavy substances, such as mineral and shell, may be used in large dosage, while light and strongly flavored substances, such as flower, leaf, and volatile aromatic herbs, are used in small dosage. Those greasy and thick in taste should be prescribed in large doses.
The dosage of a substance in decoction should be larger than that of a substance in pill or powder form. The dosage of a single-substance prescription is usually larger than that of the herb in a formula. The dosage of a substance as a primary substance in the formula is larger than that of an accessory one.
The dosage of a substance for severe, acute, and stubborn problems is usually larger than that for mild and chronic conditions. The dosage for young and strong patients is large, while that for the aged, frail, and maternal patients or for children is smaller. The dosage for children over six or under five is half, or a quarter, respectively, of the dosage for an adult. The dosage for infants should be even smaller.
Traditional weights appearing in TCM classics are different from the weight system being used in modern China. The old weight system for herbs is as follows:
i jin = i6 liang or taels i liang = io qian i qian = io fen i fen = io li i li = io hao
One liang in the old weight system is equal to 3i.25 grams. To simplify the conversion between Chinese and the metric system, China established simpler metric equivalents for traditional weight measures:
i liang = 30 grams i qian = 3 grams i fen = 0.3 grams i li = 0.03 grams preparation of herbs Decoction (tang, literally "soup") is the most common form in which traditional herbal medicine is taken in China. It is a preparation of boiling herbs with water or with a proper amount of other solvents, such as wine and vinegar. These decoctions are liquid extractions of the herbs that are absorbed easily in the human body. The contents of a decoction are easily changed to fit clinical needs. These are the reasons for the popularity of decoctions.
When preparing a decoction, substances are first put into a vessel with stable chemical properties, such as earthenware, enamel, or porcelain. Never use metal utensils such as iron, copper, or aluminum. Clean water is poured into the vessel to submerge all of the substances. After soaking for 30—60 minutes, the substances are cooked over a strong flame until the water is boiling and then simmered for 20—30 minutes. Due to the different requirements of each herb, cooking times may differ. After cooking, the liquid decoction is filtered out and saved, then more water is added to the same level as the first time, and the pot is simmered again. The same substances are usually decocted two or three times. The decoctions should be mixed together and taken two or more times a day.
The decocting period depends on the requirement of each herb. The herbs releasing Exterior syndromes or clearing the Heat should be decocted in a small amount of water with a strong fire in a short period of time, usually 5—10 minutes after boiling. The herbs with tonifying functions should be decocted in a large amount of water with a low heat for a long period of time, usually 40 minutes after boiling.
Some herbs need special treatment during the decoction process. When special treatment is needed, a note should be given on the prescription to the pharmacist. The herbs will then be packaged separately. The special treatments are as follows:
Decocted First (Xian Jian) Some substances like minerals, shells and fossils are not easily extracted and should be cooked for 15 minutes before other ingredients are added to the decoction. These substances include Gypsum Fi-brosum (Shi Gao), Concha Ostreae (Mu Li), Concha Haliotidis (Shi Jue Ming), Os Draconis (Long Gu), Carapax et Plastrum testudinis (Gui Ban), and Carapax Trionycis (Bie Jia). Some toxic substances, such as Radix Aconiti Lateralis Preparata (Fu Zi), are decocted first to reduce side effects or toxicity.
Added Later (Hou Xia) Some fragrant substances that contain volatile oils as active ingredients should be put in at the end of the decoction process and cooked for only about five minutes to prevent the loss of their volatile elements. These substances include Herba Menthae (Bo He), Amomi Fructus (Sha Ren), and some purgative substances such as Radix et Rhizoma Rhei (Da Huang), and Folium Sennae (Fan Xie Ye).
Decocted in Gauze (Bao Jian) Powder-like, sticky, or viscous substances, or plant seeds should be cooked in a gauze bag separated from the remaining ingredients. This way the decoction will not be turbid, irritating to the throat, or burnt at the bottom of the pot. These substances include Semen Plantagi-nis (Che Qian Zi), Flos Inulae (Xuan Fu Hua) and Six-to-One Powder (Liu Yi San).
Decocted Separately (Ling Jian) Some extremely expensive substances, such as Radix Ginseng (Ren Shen), Cornu Rhinocerotis (Xi Jiao), and Cornu Cervi Parvum (Lu Rong) are often cooked separately. The decocted liquid of these substances may be taken alone or mixed with other decoctions.
Taken with the Decoction (Chong Fu) Some substances unsuitable for decoction, such as Cortex Magnoliae Officinalis (Hu Po), Radix Notoginseng (San Qi), and Cinnabaris (Zhu Sha), should be ground into fine powder and infused with warm boiled water or finished for use.
Dissolved in Decoction (Rong Hua) Those gluey and very sticky substances, such as Colla Corii Asini (A Jiao) and Saccharum Granorum (Yi Tang), should be dissolved separately in a small container. The resulting solution should be added to the strained decoction of other ingredients before ingestion.
In addition to decoction, there are some other forms of herbal medicine. Pills (wan) are made by combining the fine powder of pulverized medicinal substances with a viscous medium, usually with honey. The sizes of the pills vary, and usually are prescribed with some common edible substance such as mustard seeds and long yan fruit. Tonic formula is usually made into big "honey pills" (mi wan), while other formula may be made into smaller "water pills" (shui wan). From a functional perspective, pills are usually mild and slow in action.
Another form of medicinal preparation is powder (san), a readily absorb-able, convenient, and easily stored form. The rate of medicinal action is in between that of decoction and pills. Because powders are not easy for a patient to take, the powder form is not very popular and is not good for complex formulas.
Syrups (gao) are produced by decocting substances in water, reducing the strained decoction to a thick concentrate, then adding granulated sugar or honey. This form of preparation is appropriate in the treatment of respiratory disorders such as cough and sore throat.
There are two forms of plasters ( gao) that are both used externally. Plaster medicine ( gao yao) is prepared by slowly simmering medicinal substances in oil (usually sesame oil), discarding the residue, and adding beeswax. It is then spread on paper or cloth, and applied externally. Medicinal plaster (yao gao) is the other form of plaster that is prepared by adding the powder of a formula to a heated mixture of oil and beeswax. Plasters are usually used in treatment of dermatological disorders, fractures and sprains, and immobile masses.
Modern pharmaceutical technology has led to the creation of a number of new forms of medicinal preparation in China. These include infusions, tablets, tinctures, suppositories, capsules, and drops. The new forms of preparation are usually for those formulas developed in recent decades, and some contain Western drugs. Although decoction is still the most popular form of preparation in China, other forms such as capsules or pills have become more and more popular. In recent years, the powder form of crude extracts for individual herbs and herbal formulas has appeared in the market. Extracts from individual herbs can be mixed to form formulas for clinical use. Much study and testing is being done on these new medical preparations.
Decoctions are usually taken warm. Those for expelling Wind-Cold patterns are better taken while hot. Those for releasing vomiting should be taken in small amounts at frequent intervals. Pills and powders are usually taken with warm water.
Tonics should be taken before meals. Substances irritating to the stomach and intestines should be taken after meals. Antihelminthics and purgatives should be taken on an empty stomach. Sedatives and tranquilizers should be taken before bedtime. For the substances taken before or after meals, there must be a one- to two-hour interval between the meal and the medicine to prevent the interference on the therapeutic effect from the food.
Generally speaking, medicinal substances may be taken two to three times a day. For chronic diseases, decoctions require two doses a day, one dose in the morning, the other before bedtime. For acute disorders, decoctions must be taken every four hours during the day.
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