So why don't you listen to your grandmother?

Eventually, most women develop a vaginal yeast infection characterized by burning, itching, and a thick discharge. An over-the-counter preparation such as Monistat or Gyne-Lotrimin brings relief for most of these women, and the problem does not recur. Others, however, are not so fortunate.

Long before these drugs were on the market, Grandmother had a cure for this common, miserable condition--a cure that was also said to prevent the problem in the first place. The secret? Eat lots of yogurt.

To put such folklore to the test-- or to rest--doctors at the Long Island Jewish Medical Center in New York examined for one year a group of women with chronic yeast infections. For half the year, the women ate no yogurt; for the other six months, they ate eight ounces a day.

Viola! Grandmother seemed to be right. On average, these women had one-third as many episodes of yeast infection while eating yogurt as they did during the nonyogurt period.

The researchers theorized that a live bacterium, Lactobacillus acidophilus, was the friendly helper in the yogurt. As the bacterium found its way through the intestinal tract to the vagina, it "crowded out" the yeast cells that were causing the problem. Dr. Eileen Hilton, director of the study, cautions that the findings will have to be confirmed by further studies before any sweeping claims for yogurt can be made regarding the prevention and control of vaginal yeast infections.

Chronic yeast infection sufferers may not wish to wait for more conclusive results, however. If you're fond of yogurt, you've nothing to lose by trying a daily serving of that fine food, but be aware of two things. First, the vaginal discharge may be due to something much less innocuous than a simple yeast infection. Second, most yogurt found in the supermarket doesn't contain L. acidophilus, which is killed by the pasteurization process that most yogurt undergoes to assure freedom from bacterial contamination.

Therefore, let your doctor examine you to determine whether yours is just a simple yeast infection or something more serious. Then try to find yogurt whose label indicates that the manufacturer has put back live acidophilus after pasteurization.

(One would assume that acidophilus milk might have the same beneficial effect. Unless you have a penchant for this more expensive and less tasty source of the friendly organism, however, yogurt would be the Ilkely choice.)