The possible medicinal powers of echinacea and cranberry juice were not so evident in two new studies.

One research project explored the effectiveness of echinacea in treating the common cold. In this trial, 713 persons aged 12 to 80 years, all with new-onset colds, were given either no pills, placebo pills, echinacea pills in a blinded intervention, or the same echinacea regimen unblinded.

Illness duration and severity were not statistically significant for echinacea compared with placebo. Mean illness duration in the blinded and unblinded echinacea groups was 6.34 and 6.76 days, respectively—not much shorter than the 6.87-day average for the placebo-takers and 7.03 days in the no-pill group (Ann Intern Med. 2010;153:769-777).

Placebo once again trumped the intervention in another trial, this time faring better than cranberry juice in protecting against repeat urinary tract infections (UTIs) in 319 women initially presenting with acute UTI. The women were instructed to drink either eight ounces of cranberry juice or a placebo juice b.i.d. for six months or until another UTI developed.

Although the investigators expected to see a 30% recurrence rate in the placebo group, the actual overall recurrence rate was 16.9%—and, it was higher in the cranberry-juice group than in the placebo group (20% vs. 14%, respectively). The researchers noted that the placebo juice might have inadvertently contained the same UTI-reducing active ingredients as cranberry juice (Clin Infect Dis. 2011;52:23-30).