I have read on Internet message boards that acidophilus helps keep vaginal flora in balance and is beneficial to women in other ways. Can you tell me what those benefits are? Are there long-term side effects?

Lactobacillus acidophilus is a bacteria present in both the vaginal, and gastrointestinal tract; it is important in controlling vaginal pH and maintaining a healthy balance in the vaginal ecosystem. Age, infections, antibiotic use, douching, and many other factors can interfere with lactobacilli, upsetting the delicate balance and predisposing women to overgrowth of yeast and "bad" bacteria.

There have been several studies showing that regular ingestion of acidophilus, specifically in the form of yogurt with "active cultures," decreases vaginal yeast and bacterial infections. Acidophilus is also available in supplement form through capsules and powders. The powdered form, which is mixed with water, is the most effective; unfortunately, according to my taste buds, it is also the least palatable. Give me an eight-ounce container of low-fat yogurt any day! But read the label: Not all brands of yogurt contain live and active cultures of lactobacillus acidophilus.

Acidophilus does have other health benefits. It helps prevent infection with some intestinal bugs, and seems to slightly improve general immune system function. In studies on mice, those fed yogurt with acidophilus had lower total and LDL (bad) cholesterol. Also in mice, a concoction based on acidophilus was shown to minimize radiation-induced skin damage.

Whether what's good for mice is good for men (and women) is yet to be seen. In any event, the addition of low-fat yogurt with active cultures to your diet is not a bad idea. In addition to keeping vaginal flora in balance, it's a great source of calcium. One note of caution: There can be too many lactobacillus acidophilus in the vagina. Balance is the key word. If you are using acidophilus powder or capsules, do not exceed the amount recommended on the label.