Where do complementary and alternative medicines ﬁt into modern medical practice?
Arnica for bruises, echinacea for colds: for millions of people the answer to the evils of modern life, from constipation to migraines, lies in complementary and alternative medicine (CAM).
The list of treatments is long and varied – Ayurvedic, Chinese and Tibetan herbs, acupuncture, chiropractic and reﬂexology. For some practices, there is scientiﬁc evidence of positive effects; for most, there is not.
A popular but controversial approach is homeopathy, founded 250 years ago by a German doctor, Samuel Hahnemann. He conceived the principle that ‘like cures like’. For example, onions – which produce streaming, itchy eyes – might, in minute doses, relieve hay fever. But critics are scathing. Homeopaths dilute a substance so many times that the ﬁnal remedy is unlikely to contain a single molecule of active substance. Although some have proposed that water may maintain a ‘memory’ of the active substance, there is no known mechanism by which homeopathy might work.
In addition, when put under scientiﬁc scrutiny, homeopathy fails to measure up. A recent analysis of well-conducted studies of homeopathy found no evidence that it was better than a dummy medicine (placebo).
The placebo effect should not be rubbished, however. In a typical clinical trial, around 30 per cent of people given a placebo will respond positively. The success rate of many drugs is not much better than that.
But does it work? A source of dispute is whether CAM remedies work – and how this can be judged. Support for CAM tends to be anecdotal evidence: a patient given a medication improves, therefore the medication works. This is not accepted as valid evidence by the scientiﬁc community.
Conventional medicine uses randomised controlled trials as a stern test of effect. CAM practitioners respond that individualised treatment cannot be tested in this way.
Some herbal medicines have passed stringent tests. There is now evidence that St John’s wort is effective for mild depression.Lead image:
takomabibelot/Flickr CC BY