A recent issue of the Journal of Hepatology reports on over 14 cases of acute hepatotoxicity in users of Herbalife dietary supplements in Israel and Switzerland. At least one of these cases required a liver transplant. The researchers found it difficult to interpret the findings as they could not ascertain the exact composition of the proprietary formulas, the composition of which can even vary from country to country. Thus, they could not state definitively whether or not the weight loss supplements caused the liver injury, but they thought it important to warn the public that herb-induced severe liver injury might be more common than previously thought. It is interesting to note that “ten cases of hepatotoxicity implicating Camellia sinensis [ed - tea, such as in green tea extract] have been reported” also.

From a medical perspective these reports should not be surprising. Any chemical or group of chemicals strong enough to have a clinical impact, whether “natural” or not, carries the potential for side effects. Some of these natural substances - phytoalexins - seem to have as their purpose to be noxious to pests so the pests will not consume the plant. Since from a plant’s point of view we humans might be pests - and we have some biochemical similarities to pests - some natural chemicals from plants might be noxious to us as well, especially in high doses.

The references for two of these articles are: J Hepatol. 2007 Oct;47(4):514-20, and Journal of Hepatology 47 (2007) 521–526. The PDF for one of them can be found here, if you are interested in the details:

http://www.ikp.unibe.ch/lab2/herbalife2007.pdf.