( of a TCM treatment than a Western treat...)Viagra's hidden help for wildlife

These findings stand in contrast to prior research suggesting a mistrust of Western medicine in Asian markets.

"When we proposed that Viagra might make inroads into TCM treatments for impotence, conservationists told us we were nave and that TCM consumers were unwilling to use a product outside their own medical tradition," says Bill von Hippel. "For example, there is still strong demand for tiger bone among TCM apothecaries who use it in the treatment of pain relief, despite the widespread availability of aspirin.

"But the failure to achieve an erection isn't comparable to having a headache or the many other ailments for which consumers still prefer TCM treatments. Furthermore, Viagra differs from many other Western drugs, in that the effects are rapid and visible to the naked eye.

"The fact is that prior to the commercial availability of Viagra in 1998, no product in any medical tradition had been proven to be an effective and non-intrusive treatment of erectile dysfunction. So despite their history of using traditional medicines and their alleged suspicions of Western medicine, the men we interviewed chose the product that works best."

These findings are consistent with previous research by the von Hippels showing evidence of a post-Viagra decline during the 1990s in the harvesting of three species used in TCM impotence treatments.

The pair attributed some of this decline to Viagra, despite scepticism among many academics and wildlife experts.

In 2002, the global market for TCM products and treatments was valued at more than $20 billion, according to the Chinese firm Shenzhen Matrix Information Consulting.