Do probiotics actually work?

“For three specific use cases, yes — the AGA's 2020 clinical practice guidelines recommend probiotics for preventing necrotizing enterocolitis in preterm infants, preventing C. difficile in adults on antibiotics, and treating pouchitis. For everything else (IBS, Crohn's disease, ulcerative colitis, general 'gut health,' immune support, mood) the AGA's position is that the evidence does not yet support routine use.”