I've heard Synacore is a good one, I've not used it though. I have used Bene-Bac Plus, made by Pet-Ag, the same company that makes KMR with good results, helps settle upset tummies and loose stools. For the Synacore, theres a sample for it for free, its sent to your clinic though, here is the link, http://www.vanbeekpets.com/synacore/