FAQ for Chinese Herb Basics
Q: Chinese medicinal materials are composed of?
A: Chinese medicinal materials refer to the drugs used under the guidance of Chinese medical theory; any substance can become a Chinese medicinal material.
They generally include three major categories: plant medicine, animal medicine, and mineral medicine. Plant parts such as roots, stems, leaves, flowers, fruits, and skins are used as medicine, and ancient books are often divided into categories such as grasses, woods, fruits, vegetables, and grains. Animal medicines include the whole or part of animals, insects, and marine products, and ancient books often divided into categories such as insects, fish, shells, birds, poultry, and beasts. Mineral medicines include natural minerals, processed minerals, and animal fossils that can be used for medicine.
In clinical applications, plant medicines account for the majority, other commonly used types include minerals such as gypsum and realgar; animal parts such as periostracum cicada and deer antler; animal excretions such as bezoar and flying squirrel dung (wu ling zhi); and some artificial products too.
Q: Chinese medicinal materials have how many types?
A: According to the data from the National Chinese Medicine Resources Census Information Management System, there are currently about 13000 species of wild medicinal resources in China, more than 700 species of artificially cultivated medicinal materials, and nearly 1,900 species of medicinal materials circulating in the market. The more commonly used Chinese medicinal materials are about 400 species.
Q: What are the usual dosage forms in Chinese herbal remedies?
A: Traditionally, physicians suggest their patients to boil their prescriptions with water to make a soup for consumption, the so-called decoction. In addition to the form of decoction, there are other different preparing forms, such as traditional bolus, powders, ointments, pellets, and modern capsules, tablets, granules, syrups and even injections, which are in wide variety to meet the health needs of people.
Q: What are “Four Natures” and “Five Flavors” in Chinese medicines?
A: The “Four Natures” refer to the four medicinal properties of cold, cool, warm, and hot, and the “Five Flavors” are sour, bitter, sweet, pungent, and salty. These medicinal properties of Chinese medicines are summarized by the ancients based on the different reactions that appear after the medicines acted on the human body. For example, when people experience heat symptoms such as dry throat, constipation, and yellow urine, they can be relieved by taking herbs like golden thread rhizome and Chinese rhubarb, indicating that these herbs are cold or cool in property. If someone experience chills, fever, runny nose, and body aches that present a wind-cold syndrome, herbs like notopterygium root and ginger can relieve the signs, and therefore the herb can exert a warm and hot property. As for the Five Flavors, they will have different effects, for example, pungent herbs such as fresh ginger and onion have a sweating effect, sweet herbs such as red dates and pilose asiabell root have a tonic effect.
Since the Chinese medicines have different natures, flavors and attributions, which help evaluate their clinical actions, and so can be classified accordingly.
Q: What are Ascending, Descending, Floating, and Sinking effects in Chinese medicines?
A: These different "spatial" effects reflect the working tendencies of Chinese medicines.
An "ascending" effect enables the herbs to exert the upward movements or work on the upper body e.g. arresting diarrhea or holding organs in their proper places (to prevent them prolapse or sinking); a "descending" effect enables the herbs to exert the downward movements e.g. relieving vomiting, hiccup, coughing and panting; a "floating" effect drives the medicinal properties to exert the outward movements, e.g. inducing perspiration and dissipating body heat; while a "sinking" effect means consolidating and restricting, enabling the facilitation of urination and defecation.
Since different diseases have various developmental tendencies (moving upwards, downwards, spreading outwards and moving inwards), herbs are used to counteract these tendencies in the diseases and relieve their symptoms. For example, in Influenza or common cold, TCM believes that the lesion lies on the upper and exterior part of the body, and so physicians select herbs with lifting and floating effects such as ephedra and cassia twig in the prescription, herbs that have descending and sinking effects should be avoided.
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| Ascending effect | Descending effect | Floating effect | Sinking effect |
Q: What is meant by apply herbs according to the meridians?
A: Applying herbs according to meridians is to demonstrate the position where the herbs will have the most effect on. Chinese herbs are grouped according to their energetic properties, meridians in here mean the different organs that are linked by the energetic channels.
There are some herbs that work on only one meridian, but others can work on several meridians. Selecting and combining herbs according to the target meridians help raise the efficacy of the herbs. For example, herbs with a cold nature and clearing action can target on different organs, some herbs tend to clear liver fire, some herbs clear stomach fire, and others clear heart or lung fire.
Since the meridians or internal organs are interrelated and influence one another physiologically and pathologically, it is necessary to consider these interrelationships too. Therefore, most TCM physicians usually select herbs that match more than one meridian.
Q: How are herbs selected and combined in TCM prescriptions?
A: In TCM, herbal therapies are generally formula based and single herbs are rarely used. TCM holds that every medicinal substance has its strengths and its shortcomings, and each ingredient in the formula should be carefully balanced in quality and quantity, in order to accentuate its efficacy while reducing side effects.
Herbs can complement and assist each other in certain combinations, physicians are likely to prescribe for the following purposes:
- Mutual Need (相須): This refers to the combination of herbs with similar properties and effects to enhance the original therapeutic effects. For example, when anemarrhena rhizome and gypsum are used together, their effects of heat-clearing or fire-purging are significantly enhanced.
- Mutual Enhancement (相使): This refers to the combination of herbs with the same or different properties, one as the main herb and the other as the adjuvant, to enhance the efficacy of the main herb. For example, when golden thread rhizome is used to treat dysentery, costus root can assist by smoothing bowel movements and arresting abdominal pain.
- Mutual Counteraction (相殺): This refers to one herb being able to reduce or eliminate the toxic side effects of another herb. For example, mung beans can kill the toxicity of croton.
- Mutual Restraint (相畏): This refers to when two herbs are used together, the toxicity or efficacy of one herb is inhibited by another. For example, pinellia and arisaema are restrained by fresh ginger.
- Mutual Antagonism (相惡): This refers to when two herbs are used together, one herb weakens the original effect of another herb, such as the invigoration effect of ginseng can be inhibited by radish seed, fresh ginger reduces the effects of baical skullcap root.
- Mutual Inhibition (相反): This refers to when two herbs are used together, they produce strong side effects; for example, liquorice root will increase the toxicity of lilac daphne flower bud.
- Single Use (單行): This refers to a herb used alone in order to exert its own specific action, e.g. ginseng alone is enough to replenish inborn qi in a short time.
In fact, the ways of mutual restraint, mutual antagonism, mutual inhibition are usually regarded as the contraindications of herbal applications, however these are not absolute and are for reference only. In real practice, physicians may prescribe like that for their patients, with a cautious manner.
Two well-known herbal groups of contraindications that must be grasped by every TCM student are the “Nineteen Anti” and “Nineteen Fear”.
Q: What are “guiding herb”? How do they work in TCM prescriptions?
A: A guiding herb is used to enhance overall efficacy of the prescription, harmonize actions between ingredients, reduce toxicity or harshness, correct taste, or enable other ingredients to work on specific meridians.
- Harmonize and enhance the actions: For example, in wind-heat type influenza when individuals present with a high fever and thirst, bamboo leaf and reed rhizome are used. The two herbs work together can strengthen the effects of clearing heat and bringing down the fever.
- Guide other herbs to work on specific meridians: For example, pain in the lower limbs and feet, achyranthes root is usually selected to act as a guiding role, so that other herbal effects travel to the painful location.
- Reduce toxicity: Large blister beetle is usually prescribed to treat liver cancer; however this insect is very toxic, mung beans would also be used as the guiding herb to prevent harmful effects from occurring.
- Improve taste: For example, the fishy smell of some animal products can be eliminated by millet wine. Ingredients like honey, malt sugar and sugar cane juice are often used to make herbs more palatable.
Q: What is Chinese medicine decoction pieces?
A: TCM professionals traditionally named the unrefined Chinese medicine as Chinese medicinal materials, which include three major categories, plant medicines, animal medicines, and mineral medicines. The plant medicines accounting for the majority. If Chinese medicinal materials are processed, selected, prepared, and sliced to facilitate the dispensing of TCM physicians, they are called decoction pieces.
Q: How is the dosage of each ingredient in TCM prescription determined?
A: The dosage of each ingredient in a TCM prescription is determined by the nature, texture, dosage form, and combination of the herbs, and patient’s condition should also be considered, such as age, body constitution, and severity. Physicians will generally consider the recommended dosage listed in pharmacopoeia when prescribing, but each physician may have individual preference based on their experiences.
In clinical practice, potent Chinese medicines will use in limit dosage, and those general herbs can be larger; if the herbs are light weight and loose texture, such as flowers and leaves, the dosage is less, and those heavy minerals and shells is larger. Generally, the dosage for decoction is larger than that of pills and powders; the dosage for single herb is larger than that of formula; children and elderly should be small dosage; acute diseases use larger dosage, and chronic diseases can be less.
Q: What Chinese medicines belong to endangered species, and have been prohibited to use?
A: China has made the “National Key Protected Wild Medicinal Material Species List” for that purpose, in which the endangered wide species are divided in three grades. The listed WILD species are protected by law and prohibited to use.
- I Grade: Rare and precious wild medicinal material species on the verge of extinction, such as tigers (tiger bones), Saiga antelopes (antelope horns), sika deer (sika deer velvet), etc.
- II Grade: Important wild medicinal material species whose distribution area has shrunk, and the resources are in a state of exhaustion, such as liquorice root, ginseng, golden thread rhizome, eucommia bark, and tokay etc.
- III Grade: Major commonly used wild medicinal material species with severely reduced natural resources, such as ledebouriella root, Chinese senega, Manchurian wildginger, and dendrobium etc.
* It should be noted that most ingredients prescribed by physicians are cultivated, because they are more reliable and affordable resources, wild medicinal materials are rarely prescribed nowadays.
Q: What are authentic medicinal materials in TCM?
A: This refers to those that belong to a specific geographical origin and production area, processed locally, with a recognized source, and have a definite and reliable therapeutic effect. The efficacy of a Chinese medicines is determined by the amount of active ingredients it contains, and the amount of active ingredients is closely related to the ecological growing environment of the herb, such as soil, water quality, climate, etc. The famous authentic medicinal materials include angelica root from Gansu province; wolfberry from Ningxia province; golden thread rhizome, Sichuan lovage rhizome and unibract fritillary bulb from Sichuan province; poria and notoginseng from Yunnan province; cordyceps from Tibet; Asian ginseng from Jilin province. Most physicians prefer to use these authentic medicinal materials to ensure the quality and therapeutic efficacy of their prescriptions.
Q: What is the purpose to process Chinese medicinal materials?
A: The purpose of processing can be summarized as below:
- Reduce or eliminate the toxicity and side effects of drugs: Herbs like aconite root, common Monkshood mother root, Kusnnezoff Monkshood root, pinellia tuber, Jackinthepulpit tuber, and nux vomica are very likely to be poisoned when taken orally; their toxicities and irritations can be greatly reduced after being processed.
- Enhance efficacy: For example, honey-roasted common coltsfoot flower has better moisturizing and cough-relieving effects than its raw one; and pinellia tuber processed with ginger juice can enhance its antiemetic effect.
- Change the medicinal properties of herbs and widen their applications: For example, fresh rehmannia root is used to cool blood, while processed rehmannia root can nourish blood; medicinal evodia fruit is used to stop vomiting by stir-fried with golden thread rhizome solution, to treat hernia by processed with salt, to expel coldness and relieve pain by processed with ginger, to calm the liver and relieve pain by processed with vinegar, and to relieve qi stagnation in the heart or abdomen by processed with wine.
- Change the target parts or enhance tendencies of drug action: A Chinese herb can have multiple effects, that are not all applicable to a certain clinical condition. For example, ephedra is mainly for respiratory problems especially asthma or cough, however for those who accompanied with sweating, the herb’s perspiring effect is not favorable. After being roasted with honey, this unwanted effect is restrained, the asthmatic or cough arresting effect is enhanced too, making ephedra suitable for asthmatic or coughing conditions.
- Convenient for dispensing and preparation: For example, mineral and shell-like drugs with hard texture must be processed to make them crispy, which is convenient for preparation, also helps the release of active ingredients.
- Maintain purity: Most Chinese medicinal materials cannot be used in raw, as various impurities are often mixed, a certain standard of cleanliness and purity must be achieved before use.
- Facilitate storage and use: the usual procedures like roasting, baking, and frying can absorb the moisture of medicinal materials, kill insect eggs, and remove special odors. Processed with wine, salt and vinegar can be preserved for longer time.
Q: How to identify the quality of Chinese medicines?
A: Since Chinese medicinal materials are mostly originated from nature, the active ingredients contained in them vary greatly due to geographic environments, this results in different grades of medicinal materials.
In general, authentic medicinal materials are better, but they should also be considered with appropriate harvesting time and processing methods. It is traditionally believed that wild medicinal materials are superior to the cultivated ones, however this is not absolute nowadays. Qualities such as size, shape, color, luster, texture, flavor, smell and cleanliness of medicinal materials should all be considered when choosing Chinese medicinal materials. It is best to go to a reputable herbal store and ask an experienced Chinese pharmacist for help.
Q: How to store Chinese medicinal materials?
A: If Chinese medicines are not stored properly, their effectiveness could become compromised. This is indicated by certain physical changes, like appearance or smell. Worm infestation and mold can also occur if the medicinal material has been stored in a place with a high room temperature and humidity (>70%) or when the medicines have a higher water content. In such case, medicinal materials could also lose their essential oils and become “oiling”.
To avoid the above, place Chinese medicinal materials in a dry, well-ventilated and dark place. Ideally, storage in a cool place will lessen the likelihood of mold or pest infestation occurring. Regular inspecting is also required during the storage period.
Written by:
CM Promotion Group - School of Chinese Medicine, CUHK.
References:
Chinese Pharmaceutics Chinese Pharmaceutics Identification Published by Shanghai Science and Technology Publishing House, 6th edition.
Translated and Edited by:
Jennifer Eagleton, BA, MA (Asian Studies), Integrated Chinese Medicine Holdings Ltd.
Lawrence Lau, Ph.D., Integrated Chinese Medicine Holdings Ltd.
Rose Tse, Integrated Chinese Medicine Holdings Ltd.
