what do you guys here think of probiotics to take care of the gut?

i was taking vitamin bounty pro 50 probiotics for a while and i improved... but i don't know if it was the probiotics of the other parts of the protocol that were helping me. when i ran out i recently tried s boulardii probiotics per recommendations i've seen, but i got pretty sick when i started taking them so i stopped.

what do you guys think? obviously, one of the big parts of pfs is the gut and i just want to be proactive on that front. not cutting corners here, as i know the rest of the protocol has to be dialed in. that being said, are there any probiotics that you guys have taken that you find helpful and recommend?