I've only ever taken pill form probiotics after a course of antibiotics.
Been known to have the odd probiotic drinking yogurt (various brands) but hear that it is not as likely to survive to reach the gut where it might do some good.
The evidence may be only anecdotal but there seems to plenty of that.
The manufacturers make no inflated claims, in fact, it says on the container; 'Daily value, not established'.
It also says that each cap. contains 3 billion of them - an awful lot of whatever they are, maybe enough for one or two to do some good. :0)
That's the weakness of the studies I suppose. And the strength of advertising...telling us we *need* them. Studies need to be done with ibs patients and others who might benefit.