Probiotics, microorganisms that actually benefit the body by helping to fight disease and maintain the health of the intestinal tract, have become quite popular as nutritional supplements. Indeed, since January 2002, their sales in natural-products supermarkets have grown by more than 14 percent; more than 3.5 million units have been sold.

Unfortunately, a third of the probiotic supplements recently evaluated by ConsumerLab.com contain fewer than the recommended 1 billion or more organisms per daily serving. ConsumerLab.com’s review also found that probiotic supplements labeled as containing specific numbers of bacteria were more likely to contain enough of them than were probiotic supplements either labeled as containing certain numbers of bacteria only at the “time of manufacture” or not labeled at all. ConsumerLab.com (www.consumerlab.com) provides its subscribers general information about buying and using probiotics and a list of all supplements that it found to contain sufficient amounts of probiotics.