I'm not really sure why people are so enamored of peer reviewed studies. Depending on your methodology, you can get them to prove anything. We've had peer reviewed studies that prove hormone replacement therapy is helpful, that it's harmful, that it works, that it doesn't work, and that in only works for five years around menopause. If you can get a peer reviewed study to come out with continually contradicting results, how much value can it have?
Which brings us to Echinacea!
A peer reviewed study released today finds that Echinacea is effective at preventing and reversing colds. This is in total contradiction of several previous peer reviewed studies that proved it didn't. At the time, I said the previous studies used flawed methodologies.
Is the new study using better methodology? Not necessarily, although it claims to – and claims the previous studies used flawed methodology. Although peer reviewed studies are considered the Holy Grail of medicine (I am often asked, “Where are your peer reviewed studies on alternative health treatment?”). They aren't really that reliable. You can get them to say anything.
In the end, anecdotal evidence, especially when it comes from centuries of report, has equal validity.