Probiotics are types of bacteria or yeast that have health benefits. They help keep the natural balance of organisms in the intestines. They reduce the growth of harmful bacteria to help keep the digestive system healthy. A common type of probiotics found in food is lactic acid bacteria. It's in foods like yogurt, sauerkraut, and kimchi.

Why are probiotics used?

Many people use probiotics to prevent side effects from antibiotics. Antibiotics kill good bacteria along with the bad bacteria that cause illness. A decrease in good bacteria may lead to digestive problems like diarrhea, gas, and cramping. It may also lead to infections such as vaginal yeast and urinary tract infections. Taking probiotics may help replace the lost good bacteria. This may help prevent diarrhea and infections.

Probiotics may also be used to help with:

• Other causes of diarrhea.
• Preventing infections in the digestive tract.
• Controlling inflammation, as in inflammatory bowel disease.

Some people think probiotics may help treat problems in the stomach and intestines. But only certain types (strains) of bacteria or yeast have been shown to work in the digestive tract. Experts still need to find out which probiotics might work to treat specific diseases. They are studying probiotics for possible benefits in colon cancer, skin infections, and irritable bowel syndrome.

How safe are probiotics?

Most probiotics are like the bacteria that are already in your digestive system. Some probiotics have been used for a very long time. Examples include those in fermented foods and cultured milk products. These appear to be safe for most people. But more study is needed to be sure that probiotics are safe for young children, older adults, and people who have weak immune systems.

Be aware that probiotic supplements are regulated as foods, not drugs. If you take a supplement, be sure to tell your doctor about everything you take, including the specific bacteria or yeast in your supplement.