Is probiotic powder effective?is buttermilk or curd a probiotic?any natural probiotics?doc has asked me to take probiotics but need a reliable brand

Perhaps, marketing: yet few clinical trials, little reliable data. Like many OTC products, labels often do not even match contents. While some data about probiotic benefits with clostridium difficile & ulcerative colitis exists, few reliable brands. Thus natural fermented products likely a better option for now. Study the: "Human Microbiome Project" for insights; >another decade to sort out some of the complexity.