Chinese men are selectively switching from traditional Chinese medicine (TCM) to Viagra to treat erectile dysfunction, but sticking with tradition for ailments such as arthritis, indigestion and gout, according to new research published in Environmental Conservation.

The finding supports a prediction made by Australian and Alaskan researchers at the advent of Viagra's commercial release in 1998 that the new impotence drug might reduce demand for several animal species that are over-harvested to treat impotence with TCMs.

Animals such as seals, sea horses and tigers have long been hunted because practitioners of TCM use their body parts for their presumed healing and virility qualities.

The researchers surveyed 256 Chinese men, aged 50 to 76, who sought treatment at a large TCM clinic in Hong Kong. The men were questioned about their previous and current use of TCM and Western treatments for arthritis, indigestion, gout and impotence.

The study's lead authors are Dr Bill von Hippel, a psychologist from the University of New South Wales (Sydney, Australia), and his brother, Dr Frank von Hippel, a biologist from the University of Alaska, Anchorage. The von Hippels cite three key findings from the research.

"First, significantly more men had formerly used a TCM treatment for impotence than were current users," says Bill von Hippel.

"Second, they were significantly more likely to be using a Western treatment for impotence than a TCM treatment.

"Finally, among men who formerly used either Western or TCM treatments for impotence, they were more likely to switch from a TCM treatment to a Western drug than vice versa. In fact, nobody had switched from a Western drug to a TCM treatment for impotence.

"This was in contrast to their behaviour with the other three ailments - arthritis, indigestion and gout, where the men were more likely to be current users of a TCM treatment than a Western treatment."

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 na�ve 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.