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Adulterated Chinese herbal medicines


Chinese herbal medicines are becoming more popular, and there is even evidence that they might work. Bandolier 60 reported on positive results from a randomised trial in irritable bowel disease, and there are suggestions of efficacy in respiratory tract infection, eczema and even hepatitis B from systematic reviews of, admittedly, generally poor studies.

One of the problems, though, is that these herbal medicines are not standardised, and usually contain many ingredients. A review [1] tells us that some of those ingredients can be synthetic drugs, responsible both for good effects, and for serious harm.


At least six databases were searched up to December 2001 for studies that might report on the adulteration of Chinese herbal medicines. Electronic searching was supplemented by other forms of searching, including personal databases, and letters to experts and manufacturers.

Studies of any architecture were accepted, case reports and series, and analytical investigations. Studies had to specify the medicine in sufficient detail to identify it as a recognised Chinese herbal medicine.


There were 22 relevant articles, 15 case reports, two case series and six articles about analysis of Chinese herbal medicines. Most reports originated in Western countries, but there was one each from China, Taiwan and Japan.

The range of adulterants found is shown in Table 1, and included steroids, NSAIDs, anticonvulsants, benzodiazepines, hypoglycaemic agents and drugs used for treating erectile dysfunction. The problems they caused are also shown in Table 1, and included a number of serious adverse effects possibly or probably related to adulterants.

Table 1: A list of adulterants found in Chinese herbal medicines, and problems caused by adulterants

(note that problems and adulterants are not linked in these lists)

Adulterants found

Problems caused

aminopyrine agranulocytosis
caffeine arrhythmia
chlorzoxazone coma
clobetasol proprionate Cushing's syndrome
diazepam diabetes
diclofenac increased INR
dexamethasone hypertension
ethoxybenzamide hypoglycaemia
fluoconolone acetonide gastrointestinal bleeding
glibenclamide septic shock
mefenamic acid  
paracetamol (acetaminophen)  

What proportion of Chinese herbal remedies contain adulterants is not clear. Analysis of 2,600 samples in Taiwan showed that 24% were adulterated with at least one synthetic medicines. In a series in the USA it was 7%. The case reports showed that two or more adulterants were present in 14 of 15 Chinese herbal medicines.


There was one death reported in these reports, and at least six potentially life threatening events. Suspicion of adulteration was based not only on adverse effects, but suspiciously good efficacy. Chinese herbal medicines may work because of the adulterants.

Most people consider alternative therapies to be safe, and often do not mention that they are using them. Given that multiple adulteration of Chinese herbal medicines seems to be common, there is potential for problems, especially when other treatments are being prescribed. Imagine an older patient on NSAID and aspirin additionally taking a Chinese medicine containing indomethacin or phenylbutazone!

We simply do not know what the rate of adulteration is. One UK study of 11 herbal creams showed that eight contained dexamethasone at concentrations up to 1.5 mg/gram of cream. In the absence of better information, we should assume that Chinese medicines are adulterated.

Biochemistry laboratories in our hospitals have the capacity to look for adulterants using techniques as standard as thin layer chromatography to gas chromatography with mass spectrometry. There are a few papers and theses to be gained in this area, while helping protect patients and public from a dangerous fraud.


  1. E Ernst. Adulteration of Chinese herbal medicines with synthetic drugs: a systematic review. Journal of Internal Medicine 2002 252: 107-113.
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