Clinical Briefs

With Comments from John La Puma, MD, FACP

Hidden Toxic Ingredients in Asian Patent Medicines

November 1998; Volume 1: 132

Source: Ko RJ. Adulterants in Asian patent medicines. N Engl J Med 1998; 339:847.

Asian patent medicines comprise herbs, plants, animal parts, and minerals, which are formulated into tablets, pills, or liquids for ease of use. However, many patent medicines manufactured in Asian countries contain toxic ingredients, such as heavy metals, as well as prescription drugs or unapproved ingredients that may or may not be identified on the label.

To establish a computer base for Asian patent medicines, to educate others, and to provide objective information about toxicity, the California Department of Health Services, Food and Drug Branch studied 260 Asian patent medicines collected from California retail herbal stores. Gas chromatography-mass spectrometry and atomic-absorption methods were used. At least 83 (32%) contained undeclared pharmaceuticals or heavy metals, and 23 had more than one adulterant.


Asian patent medicines smell of mystery and funk. Where are they from? The streets of urban Chinatown, especially in San Francisco, are layered with tables of boxed and sprawling produce. A little further in, sandals and ginseng roots from all parts of Asia, and dumplings stuffed with pork and bean paste carefully lifted from the steamer can be yours for little money.

Behind the tables, the sandals, and the dumplings are modern Chinese apothecaries filled with indecipherable scripts, teas of every imagining, cups for cupping and herbs for moxibustion and spleen dampness and infertility. Now, these herbs are wafting high above Chinatowns in San Francisco and Sacramento to Costcos and Sam's Clubs near you.

Of the 31 compounds which Ko, a PharmD and PhD, found to contain pharmaceutical ingredients, only 14 noted them on the label. Ephedrine, chlorpheniramine, methyltestosterone, and phenacetin were among those not listed.

Twenty-four products contained a median of 30 parts per million (ppm) of lead; 36 contained a median of 180 ppm of arsenic; 35 contained a median of 329 ppm of mercury. Ko notes that the U.S. Pharmacopeia "limits heavy metals in most oral pharmaceuticals to 30 ppm, with lower limits for lead, arsenic, and mercury."

Adulteration by synthetic and natural therapeutic and pathogenic substances of traditional Chinese medicines is commonplace. Such medicines have been reported as potential sources of mercury poisoning—and one studied medication contained 114,000 ppm of arsenic!


Physicians who counsel patients who seek to use traditional Chinese medicine made in Asia should warn them of the high prevalence of toxic ingredients. It is a safe bet that batch inconsistency is the rule here. Whether American manufacturers can do any better, assuming that there is something to do better with, remains to be seen.