No proof that echinacea keeps colds at bay

It is a herbal supplement reputed to boost immune systems and ward off colds and flu.

Once prized by native Americans, echinacea pills, juices and teas line the walls of most health food and chemist's shops.

However, experts are now claiming that the herb may not have any effect. American researchers say it is of no use at all in keeping colds at bay.

The study, published in the journal Clinical Infectious Diseases, involved giving either echinacea or a placebo to 48 volunteers, before exposing them to a cold virus. Nine out of 10 volunteers in both groups came down with bad colds.

"The results clearly show echinacea is useless," said Dr Steven Sperber, who led the study. "Although widely used, a number of well-designed studies show it not to be effective in preventing the common cold."

The latest research backs up several recent studies.

Echinacea purpurea, or purple coneflower, is one of Britain's most popular herbal therapies and is sold in supermarkets. Fans include actresses Claire Sweeney

and Jenny Seagrove.

Dr Sperber said the public were being misled and did not really understand what they were buying. "The medications may not be standardised from one brand to another," he said.

"The particular components of the plant and the amounts of active ingredients may not be the same. Echinacea is not regulated the same as an approved drug."

Herbal remedies can be sold without prescription despite some having potentially harmful effects. Some, such as arsenic, can prove fatal if taken in large quantities.

However, supporters of herbal medicine claim the latest echinacea research is biased. Nigel

Summerley, a homeopathic practitioner, said: "Echinacea is a supplement rather than a homeopathic remedy and there are several different types, and many ways to take it.

"The key is to get pure echinacea, and to only take it when you need to, during winter for example."

The European Commission is cracking down on a string of alternative treatments, amid concern that some could be harmful. From 1 August it will become illegal to sell an estimated 5,000 vitamin and mineral supplements.