Is Probiotics good for gut health?

Yes — the evidence for this is strong. Probiotics have some of the more consistently positive supplement evidence for a specific, common problem: multiple meta-analyses, including a landmark JAMA meta-analysis and two Cochrane reviews (one in children, one for C. That's reflected in an evidence score of 75/100 for its role in gut health, drawn from 10 studies, with an estimated impact on longevity rated moderate (48/100).