As long ago as 1840, German doctors discovered that the urine of people who ate cranberries contained a chemical called hippuric acid. The doctors were researching the finding that these same people had a significantly lower incidence of urinary tract infections (UTIs) such as cystitis and pyelonephritis.
By the 1960s, when doctors were dispensing antibiotics like candy, the use of cranberries to counteract UTIs had fallen out of favor. Researchers claimed that tests showed the acidifying effect of cranberries and cranberry juice was inadequate to prevent infection.
However, as late as 1994, a Harvard University study involving 153 elderly women with repeated urinary tract infections showed that regular consumption of cranberry juice cocktail decreased the frequency of UTIs. Recently, in a clinical trial yet to be published at the time of writing from Weber State University in Utah, a concentrated cranberry product in dehydrated, capsule form – equivalent to 12 to 16 six ounce glasses of cranberry juice a day – was found to be equally effective. Some health professionals recommend the capsules over cranberry juice because of the sugar content of cranberry cocktail and the unpalatable taste of the unsweetened juice.