From my experience, yes, if from traditional fermented foods such as sauerkraut or kefir. And no, if from a capsule.
However, I have gotten benefits from activating some cultures in juice for a few days that allows them to come out of dormancy. But it takes them two or three days to wake up, so perhaps if we just take the capsule, they just pass through. But at body temperature, you'd think they would be work? Maybe the combination of dormancy combined with the digestion process just renders them bunk.
All I can really speak from is personal experience. And probiotic caps are a waste of money, while traditional fermented foods have benefits far beyond just the medium.