Probiotics are live microorganisms, usually bacteria, that are similar to microorganisms normally found in the G.I. tract. Studies have found that when taken in large enough amounts, probiotics, specifically Bifidobacteria and certain probiotic combinations, improve symptoms of IBS. However, more research is needed. Probiotics can be found in dietary supplements, such as capsules, tablets, and powders, and in some foods, such as yogurt. Dr. Jones can give information about the right kind and amount of probiotics to take to improve IBS symptoms. To help ensure coordinated and safe care, people should discuss their use of complementary and alternative medical practices, including their use of dietary supplements and probiotics, with Dr. Jones.