You&#x27;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.<p>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&#x27;t a prescription, just that he&#x27;d heard good reports from his patients.<p>For myself, I took them regularly for a couple weeks afterwards, then sporadically after that as constant usage doesn&#x27;t appear to be required, at least for me.