If you’ve ever taken an antibiotic, you have also killed the good bacteria that live in your colon. Probiotic acidophilus replaces that good bacteria and, indeed, is important for your overall health and immunity. If you have indigestion, diarrhea, constipation, candida or thrush a probiotic will help. I have used and recommended PB8 for many years and tested other probiotics, too. There are more expensive probiotics and there are probiotics that contain more bacteria but PB8 is the clear winner.