Probiotics are defined as live microorganisms that, once ingested, demonstrate a beneficial effect upon the body by improving the balance of the intestinal flora. The most reliable and well-researched probiotic organisms belong to either the lactobacillus or bifidobacteria genera—lactobacillus bacteria reside mainly in the small intestine and bifidobacteria colonize the large intestine. Probiotics inhibit the growth of harmful microorganisms, boost immune function, increase resistance to infection and promote healthy digestion. However, antibiotic use and alcohol, as well as disease and aging, can disrupt the balance of intestinal microflora, thus negatively affecting the beneficial role these important microorganisms play.

Much of the research on probiotics has focused on diarrhea prevention and intestinal health, stomach ulcers, immunity and women's urogenital health. However, promising data also exists on the use of probiotics for combating Helicobacter pylori stomach infections, modulating mucosal immunity (the first line of defense against foreign invaders), reducing the risk of certain cancers, minimizing surgical complications, and decreasing serum cholesterol and oxaluria—the excess of calcium oxalate in the urine, which contributes to the formation of kidney stones. Furthermore, preliminary human studies suggest that probiotics have a positive effect in the treatment of colitis (inflammation of the colon), also known as irritable bowel disease (IBD)—a general term for a group of diseases involving intestinal-wall inflammation and characterized by recurrent crampy abdominal pain and diarrhea, including Crohn's disease and ulcerative colitis.

Probiotic Eleven

Ooh.. I have heard of probiotic drinks, can you site some? Are they expensive?

Here's one, for example:

Probiotic Eleven

There is a detailed information sheet at the link above.

Hope this is helpful.