Probiotics are live bacteria that help restore the balance of microorganisms in the intestine, boosting the immune system to fight germs. But are probiotic products really worth the expense? Yes and no, the New York Times reports. There are thousands of different probiotics, yet only some have proven effective; what’s more, no standard labelling requirement exists, so the word “probiotic” on a product doesn’t mean much. Different species of bacteria provide different results. “It’s a huge problem for the consumer to try to make heads or tails of whether the products that are out there really work,” Dr. Shira Doron, an assistant professor of medicine at Tufts, told the newspaper. Lactobacillus, for example, can be found in many products. But “Lactobacillus is just the bacterium,” said Gregor Reid, director of the Canadian Research and Development Center for Probiotics. “To say a product contains Lactobacillus is like saying you’re bringing George Clooney to a party. It may be the actor, or it may be an 85-year-old guy from Atlanta who just happens to be named George Clooney. With probiotics, there are strain-to-strain differences.” This month, Dannon, one of the biggest sellers of probiotic yogurts, settled a class-action lawsuit over Activia and DanActive yogurt products, which are meant to help regulate digestion and stimulate the immune system. As part of the $35 million settlement, Dannon will add the scientific names of its probiotic strains to packages. The company stands by its product claims.