In the early 20th century, scientific medicine emerged as the dominant model for health care in the West. Yet, despite the successes of scientific medicine, people have continued to seek treatments outside mainstream services.1 In the United Kingdom about one in 10 of the adult population consults a CAM (complementary and alternative medicine) practitioner every year, and 90% of this contact happens outside the NHS.2

Why do people turn to these therapies? Persistent symptoms and the real or perceived adverse effects of conventional treatments are the main reasons.^w1Patients value complementary practitioners viewing their predicament “as a whole” and not through the fragmenting lens of clinical specialisation or within the time pressured environment of primary care.^w2

The popularity of a clinical method should not, however, be confused with its value. The popularity of CAM may simply reflect the limitations of conventional treatments. In the past 20 years there has been substantial research on its effectiveness. By March 2004 the Cochrane Collaboration had 145 completed reviews of randomised controlled trials …