You're right. I think there was a startup on here that had done a clinical study of some formula of theirs with many specific microbes. In my case, I used a p

You're right. I think there was a startup on here that had done a clinical study of some formula of theirs with many specific microbes. In my case, I used a probiotic that contains only Lactobacillus GG (15B cells) and saw improvement after a course of antibiotics. My doctor recommended that when I asked, but said that it wasn't a prescription, just that he'd heard good reports from his patients. For myself, I took them regularly for a couple weeks afterwards, then sporadically after that as constant usage doesn't appear to be required, at least for me.