US researchers have found consuming echinacea can reduce the chances of catching common colds by 58 per cent after reviewing 14 studies. The Lancet-published research also found echinacea (Echinacea purpurea) can lessen the duration of colds by 1.5 days.

Echinacea sales have fallen significantly in the US market after negative mainstream media coverage of some studies that found it to be ineffectual in preventing and combating colds.

The review, performed by the University of Connecticut School of Pharmacy, found a majority of studies demonstrated the effectiveness of echinacea in fighting colds. One study concluded echinacea, taken in conjunction with vitamin C, could reduce cold incidence by 86 per cent. On its own, subjects were 65 per cent less likely to develop colds.

Even those directly exposed to a cold-causing virus were 35 per cent less likely to develop colds if echinacea was administered.

The researchers noted: "With over 200 viruses capable of causing the common cold, echinacea could have modest effect against rhinovirus but marked effects against other viruses."

?Echinacea may reduce the duration of illness and decreases the severity of cough, headache, and nasal congestion,? professor Ron Cutler of the University of East London told the BBC, but warned: "The true benefits, and more importantly, how the agents work remains unclear and further better-controlled actual clinical trials still have to be carried out.?

Professor Ronald Eccles, director of the Common Cold Centre at the University of Cardiff, said the work was "a significant step in our battle against the common cold".

"Harnessing the power of our own immune system to fight common infections with herbal medicines such as echinacea is now given more validity with this interesting scientific evaluation of past clinical trials.?