An abundance of good bacteria in the colon generally crowds out stray bad bacteria in your food. For generations, people have restored the balance by eating yogurt, buttermilk or other products made from fermented milk. But nowadays, you can also down a few pills that contain freeze-dried germs. These preparations are called probiotics to distinguish them from antibiotics. Unfortunately, you can't always be sure that the bacteria in the products you buy are the same strains as those listed on the label or even that they're still alive.
Probiotics are usually sensitive to both heat and moisture.
Among the most promising and most thoroughly researched probiotics is the GG strain of Lactobacillus , discovered by Dr. Sherwood Gorbach and biochemist Barry Goldin, both at Tufts University School of Medicine . L-GG, as it's called, has been used to treat traveler's diarrhea and intestinal upsets caused by antibiotics. Even more intriguing, L-GG also seems to work against some viruses, including rotavirus , one of the most common causes of diarrhea in children in the U.S. and around the world. Here the effect is indirect. In October a subsidiary of Con Agra started marketing L-GG under the brand name Culturelle.