There are many many role of lactic acid bacteria (probiotic) like infectious diarrhea, antibiotic-associated diarrhea, gut transit, IBS, abdominal pain and bloating, ulcerative colitis, Helicobacter pylori infection, nonalcoholic fatty liver disease (NAFLD), and necrotizing enterocolitis.
The other way that probiotics help is the impact that they have on our immune system. Some believe that this role is the most important. Our immune system is our protection against germs. When it doesn't function properly, we can suffer from allergic reactions, autoimmune disorders (for example, ulcerative colitis, Crohn's disease, and rheumatoid arthritis), and infections (for example, infectious diarrhea, H. pylori, skin infections, and vaginal infections). By maintaining the correct balance from birth, the hope would be to prevent these ailments. Our immune system can benefit anytime that balanced is restored, so it's never too late.
Research into the benefits of probiotics has been branching out, and new areas are emerging. Preliminary research has linked them to supporting the health of the reproductive tract, oral cavity, lungs, skin and gut-brain axis, and the prevention and treatment of obesity and type 1 and type 2 diabetes.