CHINESE HERBS: SOME THINGS TO REMEMBER
 
 

Traditional Chinese herbal medicine (TCHM) is widely practiced today, not only in Asia but also in western countries. Unfortunately, there is considerable confusion about these herbs, which ones are used, which names apply to the herbs, and how can we identify the herbs as particular plant species or other substances. Gradually, modern, scientific clinical medicine is incorporating much of TCHM, ancient claims for these herbs are being researched, and the confusion of the names is being clarified. This is a slow process, however, due in part due to some unfortunate resistance to bringing TCHM into modern, scientific medicine. Meanwhile, it is important to keep several things in mind if you use or study Chinese herbs.

1. Chinese "herbs" are not only plants. The Chinese herbal pharmacopoeia includes as many as 5000 plant and animal species and other substances called "herbs" but which are derived from animals and minerals. Animal substances include: antelope and deer horn, donkey skin gelatin, earthworms, human placenta, bat feces, cicada exoskeleton, wingless cockroach, bear gallbladder, charred human hair, toad skin secretion, and seal penis. Mineral substances, some derived from animals, include oyster shell, talc, borax, dragon bone (fossil mammal bone), amber, and magnetite.

2. One name may apply to several substances. A Chinese vernacular herb name transliterated from the Chinese characters (a name in pinyin or Wade-Giles transliteration), often refers to several different herbs, not simply one species or substance. This presents real problems in knowing which herbs and chemical constituents are included or which are most active. Here are three examples to illustrate this. A) "Dan shen" refers usually to the root of Salvia miltiorrhiza in the mint family, Lamiaceae, but in some parts of China two other species of Salvia are used and called by this name. B) Similarly, "da ji" is also called in pharmaceutical Latin "Radix Euphorbiae seu Knoxiae." This latter name hints at the multiple nature of "da ji," and in fact, this herb name refers to two species, Euphorbia pekinensis and Knoxia valerianoides. In this case, the two species are in different plant families (thus distantly related), and we can assume that their phytochemistries are appreciably different. C) A third example is even more extreme. "Jin qian cao" is an herb that is classified in the group of herbs that are claimed to "drain dampness." This one is reputed to "clear damp-heat in the liver and gallbladder," to alleviate swelling from snakebite, and to unblock the urinary tract from stones (Bensky and Gamble, page 144.) The pinyin name refers to five different plant species, in five genera, in five botanically unrelated families. If a bottle or prescription simply lists the pinyin name (often the case), there is no way to determine which plant is involved. This further assumes there was no substitution of other herbs (see next section).

3. A standard and common practice in Chinese herbalism is substitution. This is the process of substituting another herb which is presumed to have the same or similar physiological effect. Unfortunately, the identification of the substituted herb is not made clear. In effect, any particular ingredient on a label or in a prescription actually may not be found in the prescription or patent formula, but instead, another unidentified herb may be substituted for it.

4. Frequently several herbs are combined. There is a tendency in Chinese medicine not to dispense or prescribe single herbs, which may be considered too powerful, concentrated, or ineffective by themselves. TCHM has a long and intricate history of mixing herbs and customizing the prescription to the patient, so most prescriptions and all patent formulas have several to many (5 to 20) herbs. Often, one herb will be considered to be a "primary" or dominant ingredient and be present in highest proportion. A "secondary" herb will be included as supposedly synergistic to the primary herb, and other herbs will be added. The reputed health benefits are said to be due to the elaborate combining and interaction of these ingredients. From a modern viewpoint of clinical analysis and scientific research, however, this simply complicates any attempts to determine which ingredients are responsible for particular physiological effects.

5. Any plant or plant part is a cocktail of chemical constituents. Different parts of the plant may contain quite different chemical compounds also in different proportions. Because of this, there currently is a move within the herb research community and the industry to standardize herb preparations so that particular ingredients can be identified and guaranteed in measured dosages (or minimum amounts). Such standardization is essential and in the right direction toward improved herbal medicine. However, it has a long way to go and solves only part of the problem of knowing what you are taking. In Chinese herbalism today, there appears to be little if any effort underway in the direction of standardization of the chemical components in herbal remedies. This is complicated further by dispensing herbs in mixtures such as patent formulas with 15 or 20 separate herbs.

6. Because of all these factors, it can be very difficult to know exactly which drugs are involved in Chinese medicine. (drugs=chemicals=ingredients=constituents.) For the average consumer buying over-the-counter herbs or patent formulas, it is impossible to know with much certainty what is being purchased and consumed. If you have a dozen standard references handy, it is possible to determine some of the ingredients with a fair degree of accuracy. However, many ingredients simply cannot be determined because of errors or inadequacy of the herb name, or because of the possibility of herb substitution.

7. It is not easy to gather primary research references and to ferret out the best or most relevant research papers dealing with Chinese herbs and formulas. Some research identifies an herb only by vernacular pinyin or English name. Other papers report on herbs that are identified only to a botanical genus, giving no indication of which species were used. Almost no papers indicate that herb substitution was rigorously checked for and ruled out. Many papers report on patent formulas, and some of these do not list specific ingredients for proprietary, commercial reasons. All research on mixtures of herbs, regardless of quality of experimental design, must be treated with caution because of the chemical cocktail problem mentioned above. Few research papers pay enough attention to the problem of multiple names for particular herbs and the difficulties this presents in searching the literature, as for example in doing Medline searches. Many research abstracts simply mention a transliterated vernacular name such as dong quai, without indicating that the same herb is known botanically by the name Angelica sinensis. Other vernacular names are not helpful: dang gui, tang-kuei, or the pharmaceutical Latin name Radix Angelicae. This makes literature searches considerably more difficult. Lastly, nearly all popular books on TCHM are quite inadequate in dealing with this issue of the herb names. (References 18 and 19 below are the best to use.)

8. Many of the problems above also apply to all types of herbal medicine, not only TCHM. The currently explosive growth in public interest in herbs requires us to pay more attention to some of these basic realities and constraints of traditional herbal medicine, including confusion surrounding herb names. The better job we do at this, the better we will serve our patients and consumers. We need to avoid more disasters such as the now-famous Belgium Aristolochia event (see references 1 and 3 below.) If you are interested in pursuing this further in the primary literature, I suggest doing simple Medline searches for the following authors: Mel Borins; Thomas or TY Chan; Paul But; Julian Critchley; PA DeSmet; Edzard.Ernst; Ryan Huxtable; Lucinda Miller; Maureen O'Hara; Lucija Perharic; Debbie Shaw; and EQ Youngkin..

Some References:

1. Atherton, David J., et.al., "Need for correct identification of herbs in herbal poisoning," Lancet, 341:637-38, (March 6, 1993).

2. Bensky, Dan, and Andrew Gamble, 1993, Chinese Herbal Medicine Materia Medica, revised edition, Eastland Press, Seattle.

3. But, Paul Pui-Hay, "Need for correct identification of herbs in herbal poisoning," Lancet, 341:637 (March 6, 1993).

4. Chang Hson-Mou, and Paul Pui-Hay But, editors, 1986, Pharmacology and Applications of Chinese Materia Medica, World Scientific Publishing Company, Philadelphia.

5. Foster, Steven, and Varro E. Tyler, 1999, Tyler's Honest Herbal, 4th edition, The Haworth Herbal Press, New York.

6. Fratkin, Jake, 1986, Chinese Herbal Patent Formulas: A Practical Guide, Shya Publications, Boulder, Colorado.

7. Huang, Kee Chang, 1999, The Pharmacology of Chinese Herbs, 2nd edition, CRC Press.

8. Hsu, Hong-Yen, et.al., 1982, The Chemical Constituents of Oriental Herbs, Oriental Healing Arts Institute, California.

9. Huxtable, Ryan J., "The Harmful Potential of Herbal and Other Plant Products," Drug Safety, 5 (Supplement 1): 126-136, 1990.

10. Lu, Henry C., 1997, Chinese Herbs with Common Foods: Recipes for Health and Healing, Kodansha International, Tokyo.

11. Mabberley, D.J., 1997, The Plant-Book: A Portable Dictionary of the Vascular Plants, 2nd edition, Cambridge University Press. (An essential reference for plant names.)

12. Molony, David, 1998, Complete Guide to Chinese Herbal Medicine, The American Association of Oriental Medicine, Berkley Books, New York.

13. Robbers, James E., and Varro E. Tyler, 1999, Tyler's Herbs of Choice: The Therapeutic Use of Phytomedicinals, The Haworth Press, New York.

14. Unschuld, Paul U., 1986, Medicine in China: A History of Pharmaceutics, University of California Press, Berkeley.

15. Unschuld, Paul U., Chinese Medicine, Paradigm Publications, Brookline, Massachusetts.

16. Wiseman.Nigel, and Feng Ye, 1998, A Practical Dictionary of Chinese Medicine, 2nd edition, Paradigm Publications, Brooklime, Massachusetts.

17. Yu, Chen Song, and Li Fei, 1993, A Clinical Guide to Chinese Herbs and Formulae, Churchill Livingstone, Edinburgh.

18. Hu, Shiu-Ying, 1980, An Enumeration of Chinese Materia Medica, The Chinese University Press, Hong Kong. (Currently the best single reference for cross-referencing Chinese herb names; includes helpful indexes.)

19. Chiang-yao ta-tzu-tien, (Great Dictionary of Chinese Herbs,) 1977-1979, three volumes, Shanghai Peoples' Press. (In Chinese, but Volume 3 includes indexes of plants, animals and minerals in Latin.)

20. Borins, Mel, "The dangers of using herbs. What your patients need to know," Postgrad Med 1998 July; 104(1):91-95, 99-100.

21. DeSmet, P.A., "The role of plant-derived drugs and herbal medicines in healthcare," Drugs 1997 December; 54(6):801-40.

22. Shaw, D., et.al., "Traditional remedies and food supplements. A 5-year toxicologicl study (1991-1995), Drug Safety 1997 November; 17(5):342-56.
 

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Bill Burley, Seattle, Washington
billburley@seanet.com

02 December 1999 (0.002)