I have used probiotics for years. They are one of my most important supplements and I know they help me with digestion, increase immunity and eases my increasingly extreme food allergy to wheat. I think it's best to find a product that guarantees 50 billion live bacteria at expiration date, not the manufactured date (which most of them are only guaranteed at manufacturing date... you have to hunt around). Most probiotic formulas are largely ineffective by the time you buy them. I take 2 probiotic capsules twice a day, morning and night. After I run out of a current strain, I choose another strain or two.