Benefit of Probiotics: Should you take a daily dose of bacteria?

The idea of tossing down a few billion bacteria a day for your health might seem—literally and figuratively—hard to swallow. But the May issue of Harvard Women's Health Watch reports that a growing body of scientific evidence suggests that you can treat and prevent some illnesses with supplements containing certain kinds of health-promoting bacteria, called probiotics (meaning "for life").

An estimated 100 trillion microorganisms inhabit every normal, healthy bowel, where they keep pathogens (harmful microorganisms) in check, aid digestion and nutrient absorption, and contribute to immune function. If these gut-dwelling bacteria become depleted—usually because of disease, stress, poor diet, or medications like antibiotics—health problems can result.