[link|http://www.latimes.com/news/science/la-sci-echinacea25jun25,1,4172844,print.story?ctrack=2&cset=true|Los Angeles Times]
The herbal remedy echinacea can prevent colds and speed recovery from runny noses, coughs and other symptoms, according to a study published Sunday [in the journal Lancet Infectious Diseases]that could renew interest in the discredited product.

The analysis of 1,600 patients pooled from 14 previously published studies found that echinacea reduced the chances of catching a cold by 58% and shaved 1.4 days off the duration of a cold, researchers said.
Of course those who claimed no effect are claiming "bad science" and these guys are "right back at ya". I'm sure that as in 99.83% of medical and nutritional disputes both sides are right on at least that one point.