Probiotics are foods or supplements that contain live microorganisms intended to maintain or improve the "good" bacteria (normal microflora) in the body. Prebiotics are foods (typically high-fiber foods) that act as food for human microflora. Prebiotics are used with the intention of improving the balance of these microorganisms.

Probiotics are in foods such as yogurt and sauerkraut. Prebiotics are in foods such as whole grains, bananas, greens, onions, garlic, soybeans and artichokes. In addition, probiotics and prebiotics are added to some foods and available as dietary supplements.

Research is ongoing into the relationship of the gut microflora to disease. The health benefits of currently available probiotics and prebiotics have not been conclusively proved.

However, side effects are rare, and most healthy adults can safely add foods that contain prebiotics and probiotics to their diets. Future research may lead to advanced probiotics with greater potential to improve health.

If you're considering taking supplements, check with your doctor to be sure they're right for you.