Probiotics such as Lactobacillus, Bifidobacterium and Saccharomyces, found in yoghurt, kefir and other sources, are beneficial gut bacteria that are effective for IBS, acute infectious diarrhoea, antibiotic-associated diarrhea, Clostridium difficile- associated diarrhea, hepatic encephalopathy, ulcerative colitis and functional gastrointestinal disorders.
Wilkins T, Sequoia J. Probiotics for Gastrointestinal Conditions: A Summary of the Evidence. Am Fam Physician. 2017 Aug 1;96(3):170-178. https://www.ncbi.nlm.nih.gov/pubmed/?term=Am+Fam+Physician.+2017%3B96(3)%3A170-178