I had success with Bio K. It comes in tablet form, but I preferred the drink. It tastes good, similar to thin yogurt. It is fermented milk, it comes in flavours of blueberry, strawberry, plain. Taste good! It comes in a case of twelve very small containers, or half dozen. Usually in health food stores, or try Whole Foods. Each container has fifty billion cultures. You can drink half one day, close the foil lid and save the rest for next day. I don't need it anymore, but I think it cost approximately thirty to thirty five dollars per case. The numbers on my keypad is not working, so I'm spelling out figures, sorry!