|From the Food & Health Skeptic:|
Okay, while this is pretty much the result I'd have expected, (most so-called herbal remedies have either no real effect or only a very small one), and I think accords with some other studies, I do have a few caveats.
It's a small sample of people and, most crucially, it involves self reporting. Always be wary of studies that involve people reporting how they feel, though depends on whether they were given a definite list of symptoms to report on (which seems to be the case), not just the vague "how do you feel?" kind of questions (which tend to be subjective and work in favour of unconventional remedies).