Echinacea is a popular herbal remedy for preventing or treating a cold.  A study published in the July 28, 2005 issue of the New England Journal of Medicine has found that echinacea does not prevent or help treat colds. The study was funded by the National Center for Complementary and Alternative Medicine (NCCAM).  These results confirm and extend those of a previous NCCAM study published in 2003 that found a popular echinacea product was not effective in treating colds in children.

Source:  National Center for Complementary and Alternative Medicine