I buy my probiotics from GNC and, if I remember correctly, they contain around 14 million live bacteria. (Do they pay someone to sit in a lab and look at these with a micrscope, while they count 14 million of these little suckers???)
For those of you who eat store bought yogurt, (watch those carbs!) Activa has probiotics in it as well, but I'm told it's not as effective as taking the supplements.