Britain is about to embark upon the most significant development in healthcare since the creation of the NHS in 1948. At least this is what some newspaper reports seem to indicate. According to the Daily Telegraph, treatments such as acupuncture, homeopathy, osteopathy and aromatherapy will soon be available on the NHS at no extra cost to patients.

Prince Charles and Peter Hain, the leader of the House of Commons, support the action. Britain's 20,000 GPs will be instructed to refer patients to the UK's estimated 50,000 complementary medicine practitioners. Hain, who is also Secretary of State for Wales, said: "I would like to see Wales act as a model for further development of alternative medicine".

Is the country going mad or are we about to reform UK healthcare for the better? Caution has been voiced by several leading experts. Dr Hamish Meldrum, the chair of the BMA's GP committee, warned that "regulation of complementary medicine is, at least, imperfect". Dr Tony Colland, chair of the BMA's Welsh Council, urged: "With the NHS in Wales in such a critical state, any unproven or unconventional treatment is ill-advised".

Dr Richard Lewis, Welsh secretary of the BMA, says: "Much complementary medicine is not evidence-based ... but anecdotal, and until it is, the BMA would find it difficult to support funding it at the expense of evidence-based, clinically proven medicine."

Of course, complementary medicine should be used routinely where it demonstrably generates more good than harm for patients. This means that treatments have to be tested and proven to be reasonably safe, effective and good value for money. There are dozens of unproven treatments for hundreds of conditions, so even with adequate funding, it would need a decades-long effort to generate the data required.

But perhaps the British public doesn't want to wait until scientists have finally done their homework, and perhaps the UK government feels the pressure to do something positive now. Rather than running blindly into unknown territory without any concept whatsoever, we should first consider the existing evidence. What do we know beyond reasonable doubt about complementary medicine? There are numerous treatments that are backed up by excellent data from rigorous clinical trials. To name just three: acupuncture alleviates nausea and vomiting, caused, for instance, by cancer therapies; autogenic training reduces stress in a range of situations and St John's Wort helps with mild or moderate depression.

There are also numerous alternative therapies that have been reasonably well-researched without yielding convincing evidence that they work. For example: chiropractic manipulations are not superior to conventional treatments for back or neck pain, chelation therapy (an infusion into the blood, designed to eliminate excess calcium and toxins) does not help circulatory problems.

There is already sound evidence to guide healthcare decisions. Implementing it now should satisfy the government and the public. More importantly, it could improve the NHS. All that is needed is the input of independent experts who have this knowledge.

Peter Hain argues: "Our first baby was born with eczema ... and asthma. It was only when - in desperation - we turned to homeopathy and radical changes in diet that both ailments went away." But this is hardly a sound basis for decisions about the future of the NHS.

Acting on existing evidence is hardly enough. "For every one definitive piece of evidence that we have about the effectiveness of complementary therapies, there are 50 gaps," says Dr Clive Wood - the former editor of the British Journal of Holistic Medicine - of Mr Hain's plans . What we need is a firm government commitment to fund the research that is essential for filling these innumerable gaps.

The worst thing that could happen to the NHS is that we introduce double standards - opinion-based medicine in the realm of complementary therapy and evidence-based medicine for all the rest. Unfortunately, this is precisely what the incompetent waffle about "integrated medicine" seems to be about. Let's not go back to the dark ages for the sake of a politically correct election gimmick.

· Edzard Ernst is professor of complementary medicine at the Peninsula Medicine School at the universities of Exeter and Plymouth.