If you suffer from peptic ulcers or other gastrointestinal (GI) problems, you might instinctively head for the medicine cabinet. But you might be better off reaching for the refrigerator and searching for a food that contains probiotics. Although more research is needed, some studies suggest that consuming yogurt or lactic-acid producing bacteria may be beneficial for a whole range of GI troubles.

Yogurt is one of the best-known sources of "probiotics," a term that describes foods and supplements containing microorganisms that are beneficial to the GI tract. Probiotics are sometimes called "friendly" bacteria because they help to replenish good microorganisms and inhibit the growth of harmful ones.

Other probiotic sources include kefir, a fermented milk product; acidophilus milk; fermented foods like tempeh, miso and kim chi; and nutritional supplements.

"People have been talking about probiotics for years and years and years," observes dietitian Pat Baird, a nutritional consultant and columnist. "What's happening is that in the last five years or so, people had become more interested, I believe, in taking charge of their health and looking at other ways through food that they can maintain better health and longevity."

In a 2004 review article titled "Yogurt and Gut Function," which appeared in the American Journal of Clinical Nutrition, researchers said the list of health problems that respond to these good bacteria includes diarrhea, constipation, inflammatory bowel disease, lactose intolerance and Helicobacter pylori, a type of bacteria responsible for a majority of peptic ulcers.