Cure or no cure, we'll keep taking the tablets If it turns out that echinacea really is valuable both as a prophylactic and a treatment, there will be rejoicing, not to say crowing, among enthusiasts of alternative medicine, for it will vindicate folk wisdom as a source of medical knowledge. Echinacea is extracted from a North American genus of plants of that name. Apparently, it was used by native Indians as a cure for a variety of conditions including snakebite. According to Wallace Sampson, a physician at Stanford University with an interest in alternative medicines, echinacea was first marketed for use in colds by a Swiss herbalist who had been told (mistakenly) that American Indians took it for that purpose. In fact, several medical advances have resulted from doctors conducting experiments on folk remedies about which they had heard. William Withering discovered the use of digitalis in this way, and Edward Jenner the use of cowpox innoculation - which eventually led to the elimination of smallpox. But it is science that is required to distinguish between folk wisdom and folk superstition. Why can't we be immunised against colds as we can against, say, measles or yellow fever? Colds are caused by hundreds of strains of viruses, and immunity against one strain does not confer immunity against the others - which is why, according to American immunological data, elementary schoolchildren suffer from three to eight colds a year, and adults two or three. Let us suppose for a moment that further scientific tests on echinacea show that, contrary to the hopes raised, it really does not work either to prevent or to cure colds: will that be the end of its career? By no means. We each - man, woman and child - spend about £10 a year on cold remedies, most of which we know perfectly well will not shorten the duration of our colds (which, incidentally, are responsible for about 50 per cent of time lost at work through illness, so that colds are more economically than medically significant). But we are temperamentally incapable of saying to ourselves when ill, "There is nothing I can do about it," and some of the remedies give us symptomatic relief, if only by making us drowsy. About a third of people in Britain take vitamin supplements, too; we feel, in our bones rather than with our minds, that there must be a diet that will keep us healthy and free of disease. In my childhood I was given various disgusting concoctions of hot milk and honey for my colds. These days I prefer pills - provided that I can't taste them. The desire to take medicine, said the great 19th-century physician Sir William Osler, is what best distinguishes man from the animals. This is despite the fact that his near contemporary, Oliver Wendell Holmes, said that if the whole of the pharmacopoiea were thrown into the sea, it would be better for humanity but worse for the fish. The mere uselessness, or even harmfulness, of medicine has never prevented mankind from taking it.