Chinese Herbs May
Cause Kidney Failure
NEW YORK, Feb 14 (Reuters Health) -- Another report has surfaced to remind us that just because a remedy or nutritional supplement is ``herbal,'' that does not make it harmless. A team of doctors from Taiwan report the cases of 12 patients with kidney failure apparently caused by taking Chinese herbs.
``The risk of using uncontrolled herbal medicines warrants our urgent attention,'' stated the group of physicians from Cathay General Hospital in Taipei, led by Dr. Chwei-Shiun Yang. ''Obviously; the incidence of herbal medicine-induced (kidney damage) is more common than previously perceived.''
The doctors describe 12 Chinese patients seen over a 3-year period, all of whom had unexplained kidney failure. Tests showed that these patients had interstitial nephritis (inflammation of the kidney tissues) and severe damage to the kidney tubules. The only thing these patients had in common was that they had each taken Chinese herbs for some reason: for weight control, as a nutritional supplement, or to treat a non-kidney disease.
The patients had taken Chinese herbs of various kinds and from various sources, for periods of time ranging from 3 to 18 months, although several patients did not know how long they'd taken the herbs. The doctors diagnosed all 12 patients with Chinese herbs nephropathy, a condition first identified in Belgium in 1992 when over 100 patients taking ``slimming herbs'' at a weight loss clinic experienced similar unexplained kidney failure. The harmful ingredient in the herbal preparation in these cases was thought to be aristolochic acid.
But Yang and colleagues note that the role of aristolochic acid, the substance thought to cause the Belgian kidney failures, was never definitely proved. In the Taiwanese patients, no one ingredient common to all 12 patients could be identified. The doctors suggest that ``unidentified phytotoxins (plant-derived poisons) other than aristolochic acid might induce this unique toxic (kidney disease).''
Writing in the February issue of the American Journal of Kidney Diseases, Yang and colleagues suggest that ``it is crucial to investigate the possible role of herbal remedies when faced with an interstitial nephritis of unknown origin.''
In an editorial in the same issue, Dr. Jean-Louis Vanherweghem of the Universite Libre de Bruxelles in Brussels, Belgium, observes that ``numerous myths have grown around medicinal herbs and their healing powers.'' But, he warns, ''many plants contain substances toxic to humans and therefore -- not surprisingly -- to the human kidney.'' Vanherweghem calls for herbal substances to be ``subjected to the same stringent scrutiny and controls as common drugs.'' SOURCE: American Journal of Kidney Diseases 2000;35:313-318, 330-332.

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