by Subhuti Dharmananda, Ph.D., Director, Institute for Traditional Medicine, Portland, Oregon

During the past few years, a number of disturbing reports have appeared that describe contamination of Chinese herbs and herb products. In some cases, the situation is incorrectly reported or exaggerated, but in others there are cautions that practitioners should take seriously. This article is intended to help clarify the issues that have been raised and to give the reader an insider's view of Chinese herbal materials and manufacturing of Chinese herb products.

Pesticides (Applied During the Cultivation of Herbs)

A large number of Chinese herbs are collected wild, and therefore, are not subjected to any pesticides. Some cultivated plants do not require the use of pesticides because they have natural resistance to pathogenic organisms and insects. However, some Chinese herbs are grown with pesticides. Most herb growers are sensitive to the issue of pesticide use and take adequate precautions to avoid contamination of the harvested materials (for example, by ceasing use of any pesticides during the last months of growth). Many herb cultivators in China cannot afford to purchase modern chemical fertilizers and pesticides and rely, instead, on natural materials and careful cultivation techniques. Apparently, some farmers had used modern pesticides at one time and found their products rejected by importers; this was a great loss to them and deterred them from further reliance on pesticides. Regulations have been published in China requiring cultivators to follow certain practices that minimize pesticide use and residues and China has also recently adopted (July 2001) the "Green Trade Standards of Importing and Exporting Medicinal Plants and Preparations," which provides for testing of organochloride pesticides, among other tests (e.g., heavy metals, bacteria, aflatoxin). Still, some of the specific restrictions on pesticide use that are imposed in America by the Environmental Protection Agency (EPA), and other organizations, are not present in China. This means that some of the pesticides that are used in China on herbs are not permitted in the U.S. for those crops (even if permitted for other crops).

A particular problem has been noted with ginseng cultivation. Fungicide materials are used at times, because the ginseng plant is highly susceptible to fungal rot, especially during its early growth period. Care is taken to avoid applying any chemicals close to time of harvest so that natural processes (e.g., heavy rains) have time to eliminate most of the fungicides prior to harvesting. However, residues can remain. Most of the ginseng samples with fungicide residues (mainly quintozene) have been from Korea. China has been turning to woods-grown ginseng, that is, cultivating small plots of ginseng in forest settings, rather than the larger ginseng farms that had been tried earlier. This method removes the need for applying fungicides. Nonetheless, fungicides and pesticides have been detected in some samples of ginseng and notoginseng (tien-chi ginseng).

Mayway Trading Company in San Francisco, one of the largest suppliers of Chinese herbs in the U.S., has tested a large number of batches of herbs for pesticide residues. They have found none, and have claimed that they can provide pesticide-free herbs. It can be concluded that although pesticides of various types are used in growing some portion of Chinese herbs, detectable levels of pesticide contamination are not found. Springwind Herbs, in Oakland, California, has initiated a pesticide testing program. The head of the company, Andrew Ellis, has reported that most herbs prove to be free of pesticides, but that quintozene is sometimes detected in ginseng; he has sought out and found quintozene-free ginseng supplies. He also pointed out that one or more batches of tang-kuei contained residues indicating a DDT type pesticide had been used; the batch of herbs was rejected.

There is presently no reliable mechanism for certifying herb farms in China as "organic" and the emphasis on organic farming that exists in the U.S. is not currently present in China, and may not be practical under current conditions. Therefore, persons who specifically seek organically grown herbs will have to rely on Western herbs grown at certified farms in the U.S.

Fumigants (Applied after the Harvest of Herbs)

Many people apparently believe that Chinese herbs are fumigated at the ports when they arrive in America. I have never been able to find any substantiation for this claim; all authorities (including U.S. Department of Agriculture and Food and Drug Administration) have thus far denied any such general action and there are no reported mechanisms for initiating such action. Evidence of live organisms, beyond anything normally expected, can result in rejection of the shipment. Chinese herbs imported into the U.S. generally have a very clean appearance, as anyone who has seen Chinese pharmacy materials may note. Sometimes, when large batches of herbs are stored in warehouses in China prior to being distributed to their final markets, if there is a delay in distributing them, fumigants might be used to assure that the entire supply is not endangered by a rapidly-multiplying insect pest. Heiner Fruehauf, Ph.D., a frequent visitor to China who provides information for ITM, has reported on seeing such fumigation carried out in China. However, China has effective herbal fumigants as well as chemical ones available for use. The majority of Western herbs, just like all Chinese herbs, are imported; they frequently come from South or Central America and Eastern Europe, and are subject to the same rules and regulations as Chinese herbs; these Western herbs might also be fumigated in their home country during storage. Fortunately, the high quality Chinese herbs destined for foreign markets, such as the U.S. and Europe, are items that are in high demand and thus have a high turn-over, with less likelihood of needing any such long-term storage.


It was reported, by Frontier Herbs Company, that several Chinese herbs have relatively high levels of sulfur. This is the result of a processing method whereby herbs are spread on screens, underneath which is some heated sulfur. The sulfur fumes waft through the herb material and leave some residue (which is intentional). These sulfur residues are sometimes referred to as sulfites, bringing images of sulfiting agents sprinkled on restaurant lettuce or added to finished wines. However, the sulfur compounds resulting from this method of preserving the herb quality are not known to cause reactions in sulfite-sensitive individuals (sulfur is one of the most prevalent elements in the human body, and is essential to all life). Treatment with sulfur is mostly carried out on those herbs that are moist (e.g., ophiopogon) or those that discolor significantly over time (e.g., atractylodes). Some importers specifically obtain herbs that have not been sulfur treated and will mention that in their literature. There may not be any health problems that can associated with the sulfur processing as carried out in China, but those who are concerned now have a choice, at least for crude herb materials.

Irradiation (after Import)

Today, many of the herbs and spices sold in grocery stores are treated by ionizing radiation as a means of sterilization. Crude Chinese herbs are not subjected to this procedure, with one exception: certain animal materials, mainly deer antlers, are irradiated under direction of the U.S. Department of Agriculture, to assure that organisms that cause disease in animals are not carried into this country (the same requirements exist in other countries). This type of irradiation does not leave radioactive contaminants. Some manufacturers of finished products (e.g., extract powders or granules) may utilize gamma irradiation as a means of reducing bacteria counts on the finished products; this procedure does not result in any radioactive contamination.

Sterilizing Gases (Applied after Powdering)

Some Western herb companies routinely "sterilize" their herbs before putting them into capsules (the treatment substantially reduces the bacteria count to a level deemed acceptable). The treatment involves putting the herbs into an airtight chamber, introducing a gas, such as ethylene oxide, heating the chamber to about 180 degrees Fahrenheit for several hours, and then evacuating the gas and allowing the herbs to de-gas for another twenty-four hours. The same procedure is applied to Chinese herbs that are distributed by these companies. When herbs are so treated, there may be a small amount of ethylene-derived residue which arises mainly from interaction of the sterilizing gas with water in the herb materials. There is no evidence that such treatment of the herbs is necessary for any health purpose (see below). The crude Chinese herbs used for making most Chinese herb formulas for health professionals are not treated by this method.

Bacteria, Mold and Yeast

Herbs are generally free of harmful bacteria, but they do contain naturally occurring microorganisms. Bacteria assays of several Chinese herb formulas (powdered crude herbs and finished tablets) reveal total bacterial counts under 300,000 per gram. For perspective, counts below 50,000 are considered very clean for any dry natural product, and are often not attainable without some sterilization procedure. In a 1991 publication, results of an evaluation of a large number of Brazilian crude herbs was reported: total bacteria counts ranged from a few hundred to a few million per gram. Yeasts and molds are also naturally present on herbal materials. The highest total yeast/mold count thus far reported among some tested Chinese herb formulas prepared for ITM was 2,200; most of the formulas are below 250. The sterilization procedure mentioned in the section above will also reduce these counts, resulting in yeast/mold counts below 30.

The bacteria that can cause food poisoning in relative small amounts, Salmonella, is not found in Chinese herb formulas; for example, in one series of tests, no Salmonella contamination was discovered in more than 25 random samples. Recent testing of oyster shells similarly showed freedom from this bacteria (oyster meat is frequently a source of it). Salmonella is found in certain animals, such as lizards, but the gecko lizard used in making certain Chinese herb formulas is baked to destroy any of this organism that might be present. E. coli, an indicator of animal fecal contamination, is rarely found in Chinese herbs, and in those rare cases the counts have been very low. Total coliform counts (which include several harmless organisms) in the Chinese herb tablets are generally less than 500 per gram; counts below 1,000 are considered low for natural materials. These bacteria are likely to have come from the soil where the plants are grown (manure is often used as a fertilizing agent and can account for the presence of this bacteria). The rest of the bacteria on the herbs are normal components of the environment that are not considered harmful. The FDA uses total bacteria counts as an indicator of handling of the materials. An unusually high count suggests that they were stored improperly (e.g., exposed to too much moisture) or not handled in a hygienic manner.

Viruses (that May Be Present in Animal Products)

Assays have not been carried out to determine the presence of viruses in animal materials from China. A concern was raised by some American practitioners about the possibility of human viruses in placental material from China. The processing of human placenta before it is shipped to the West includes boiling followed by baking, and the material that arrives is very dry, making it highly unlikely to contain any organisms that might have been originally present. The materials are further heated and dried by the grinding process used for making powders (for pills); alternatively, it is sterilized by boiling when the material is used in making a decoction. Small amounts of any residual viable virus would be very unlikely to cause disease when consumed orally. Nonetheless, the FDA has recently restricted use of human placenta because of their general rules-regarding potential contamination-for use of human substances in medicine.

Heavy Metals

Reports that Chinese herb products were contaminated by heavy metals emerged in the late 1990s and included an extensive testing of patent remedies by the California Health Department, Food and Drug Branch, published in 1998. Two metals detected in several products, mercury and arsenic, are the result of intentional addition to herb formulas, following the belief that these compounds improve the effects of the formulas. The primary additives are cinnabar (contains mercury) and realgar (contains arsenic). Western manufacturers of Chinese herb formulas never add these compounds, so mercury and arsenic are not present in amounts higher than normally found in plants (below 3 parts per million). Lead contamination of Chinese herb formulas may occur either from intentional addition of lead compounds (rare, but sometimes done in Hong Kong) or by unintentional contamination (environmental contamination of the herb materials or factory contamination). Chinese herb formulas manufactured in the U.S. and other Western countries never have added lead compounds. The level of lead found in the imported herb materials used for manufacturing formulas is generally quite low, almost always meeting the World Health Organization standard of not more than 3 parts per million.

Western Drugs in Patent Medicines

Western drugs are present in some patent formulas made in China, and this is not always indicated on the label. A well-known case is a variety of Yin Chiao tablet ("superior quality-sugar coated") from Tianjin, which includes an analgesic and an antihistamine (it also has caffeine added). Many practitioners and consumers are not familiar with the ingredient labeling of herbs and drug ingredients, and therefore may not realize that a drug is present in a Chinese product sold in a Chinese herb shop. Although it is illegal to import such materials for sale in the U.S., they have found their way into several Chinatown shops. A product manufactured in Hong Kong, Nanlian Chuifong Tokou Wan contains a number of Western drugs, while the labeling claims the product to be free of drugs. It was discovered by the FDA after drug side effects (including a fatality) occurred, probably as a result of taking the product along with prescription drugs. This product had been repackaged under labels such as Black Pearls and San Kee, and remained available for several years. The product is illegal in Hong Kong as well as in other countries. Continued claims that the product, under a growing number of names, does not contain drugs had been investigated in Texas: those claims were unsupported. Similarly, Western drugs are used in Vine Essence Pills, and some other arthritis patents, in An Mien Pian (for insomnia), Seven Flower Pills (for hypertension), and Pe Men Kan Wan (for sinusitis), to name a few. Recently, in England, a Chinese doctor was prescribing what were described as all natural Chinese herbal weight loss pills. These caused serious adverse effects that were traced to its inclusion of the now banned drug fenfluramine.

Mayway Trading Company had several dozen commonly-used patents tested for Western drugs in 1997. Drugs were found in numerous remedies, especially those for treating common cold, influenza, sinus congestion, and other acute disorders. Typical drug additives were antipyretics (e.g., aspirin and acetaminophen), antihistamines, and antibiotics. The products were not labeled to indicate that they contain drugs. Mayway switched supply for its patents, and relies either on a well-controlled factory in Lanzhou or its own new factory established to help avoid problems such as contamination with undesired ingredients. All companies that claim testing and control of imported Chinese patents that they sell should be questioned carefully to make sure that those claims are supported by evidence.

Other Contaminants in Raw Materials

Natural products contain various natural contaminants. For example, plants naturally contain dead insects or insect parts. When FDA inspectors check herb materials, they may conduct a microscopic examination for insect parts. If the number of insects is unusually high, that is deemed a sign that the plant materials were not stored properly, and thus subject to insect infestation after harvest. Although the insects are not considered harmful, they serve as an indicator of handling, which may then suggest that there are other problems as well. Other indicators of care in herb handling include hair (from pack animals used to transport the herbs or human hairs from anyone who handles the herbs along the way), and there can be a variety of other materials that fall in among the herbs, such as paper, cloth, twine, etc., that may have been used to package the herbs. Larger items are removed at the pharmacies before the herbs are provided to manufacturers and consumers.

Additives in Manufacturing

Many people prescribe Chinese herbs that have been processed to some extent beyond the minimal processing to produce "crude" pharmacy materials. Chinese pills may be made with honey or other binders, as well as have a coating of vegetable oil. Most cough syrups and herb extracts in liquid form (in vials) are made with sugar, honey, or both. Tablets are made with flow agents, binders, and coatings. Sugar-coated tablets and capsules made in China may have synthetic colors as aids to identification. Capsulated herbs contain flow agents and the capsule is made from animal gelatin (vegetarian capsules are rarely used and are made of the same materials used to coat tablets). Dried decoctions are often produced with a starch carrier (such as potato starch) or from the powdered herb dregs left over from the extraction procedure. For products made in the U.S., most manufacturers provide a list of items that are not used in the product which consumers may be concerned about (e.g., corn, soy, wheat, animal materials, etc.). Some manufacturers provide disclosure of all additives used in manufacturing. Typically, these involve various cellulose materials (fillers, disintegration aids, binders, coatings), magnesium stearate (flow agent), and various types of gums (binding agents). In most cases, all the additions to the basic herb material constitute less than 10% of the weight of the finished product (with the exception of products comprised of isolated active components, which may have a larger proportion of filler to control the dosage amount).

Growth of Bacteria, Fungi, or Insects after Purchase

Chinese crude herb materials may deteriorate after purchase, especially if moisture levels are high and if they are stored in warm rooms. Since many practitioners maintain a pharmacy in their clinic and the clinic is warmed for patient comfort, this can be a problem. Insect eggs, which accompany some crude herb materials, may hatch. If herbs are stored together (e.g., in bags or boxes, not in glass bottles), cross contamination of insects can easily occur. Bacteria and fungi may grow on herbs that are especially moist (e.g., jujube, biota). Such materials, if they are to be stored for an extended period of time, should be refrigerated. Crude herbs need to be examined regularly for evidence of developed contamination; if found, the bottles must be emptied and cleaned thoroughly. Manufactured products do not suffer from these same problems.

Incorrect Herb Material Provided

Another type of "contamination" is receiving an incorrect herb material; thus, the one that is not actually desired contaminates the finished product. In the case of Chinese medicine, herb substitution is a common practice, and whether or not an herb is "correct" or not may depend on certain expectations. When ordering Chinese herbs, there is a possibility that the material obtained will not be the one requested, and if the recipient is not familiar with the appearance of the proper material, then a wrong item may be used.

One of the recent problems encountered with Chinese herbs was the use of various Aristolochia species as a source of commonly used herbs, such as stephania (expected source: Stephania tetrandra) and akebia (other sources are Akebia quinata or Akebia trioflia, or Clematis armandii). From the perspective of the suppliers in China, the materials provided were the correct ones, even though the botanical origins were not correct from the perspective of the importers who had a different expectation. In the case of Aristolochia plants, this misunderstanding about botanical sources was critical: herbs from this family of plants have been reported to cause rare cases of renal damage, with potential for renal failure.

Labels on some packages of imported Chinese patents are sometimes deceptive. In some formulas, aconite is labeled as cyperus, and in a number of products, "ginseng" appears in the name of the product but not among the ingredients (it is substituted by codonopsis); a recent label for Wuchi Paifeng Wan does not show that black chicken is present, even though it is a major ingredient. Items said to contain musk, ox gallstone, rhino horn, pearl, or other expensive items may contain various substitutes; in the case of musk, the substitute may be a synthetic chemical (muscone). None of the Chinese patents tested by the U.S. Fish and Wildlife Department showed evidence of containing the endangered animal species, such as rhino horn or tiger bone, that were listed on their labels.

Steps Being Taken to Avoid Problems in the Future

American manufacturers are being alerted to problems that have arisen with materials from China and are instituting measures aimed at avoiding them in the future. Several Chinese factories, interested in supplying the Western market, are similarly taking such steps. Among the steps being taken are hiring additional quality control personnel, testing raw materials and products thoroughly, and complying with the laws (which are now being enforced more stringently). Knowledge and awareness of the issues involved in herb purity and cleanliness are the primary means of overcoming the problems. Of course, it will not be possible to eliminate all such difficulties, but by minimizing them and by having herb users aware of what to look out for, one can assure a bright future for Chinese herbs worldwide.

March 2002

quality control equipment and personnel at the Minshan factory in Lanzhou

Photos of quality control equipment and personnel at the Minshan factory in Lanzhou that supplies acceptable patent remedies for the U.S. market.