Drinking cranberry¹（蔓越橘） juice has been recommended to decrease the incidence of urinary tract²（尿道） infections, based on observational studies and a few small clinical trials. However, a new study published in the January 1 issue of Clinical Infectious Diseases, and now available online (http://cid.oxfordjournals.org/content/52/1/23.full), suggests otherwise. College-aged women who tested positive for having a urinary tract infection were assigned to drink eight ounces of cranberry juice or a placebo³ twice a day for either six months or until a recurrence⁴ of a urinary tract infection, whichever happened first. Of the participants who suffered a second urinary tract infection, the cranberry juice drinkers had a recurrence rate of almost 20 percent, while those who drank the placebo suffered only a 14 percent recurrence.

"We assumed that we would observe a 30 percent recurrence rate among the placebo group. It is possible that the placebo juice inadvertently（不注意地） contained the active ingredients that reduce urinary tract infection risk, since both juices contained Vitamin C," explained study author Betsy Foxman, PhD, of the University of Michigan School of Public Health in Ann Arbor⁵. She added, "Another possibility is that the study protocol⁶ kept participants better hydrated（含水的） , leading them to urinate more frequently, therefore decreasing bacterial⁷ growth and reducing urinary tract infection symptoms."