I know a lot of people on here are not crazy about using metronidizole, but I keep it on hand for situations like this. It clears up the problem so quickly and I've never had a dog have any reaction to it. I usually only give it for about 3 days, but it's enough to get them back on track. Sometimes it takes Metro to kick that diarrhea in the butt (no pun intended... ).
Kris ~~~~~~~~~~~~~~~~~~~~~~~~ Samson, GSD, 10/13/07 Annabel, Keeshond, 4/21/11 Petie, Toy Poodle, 5/5/07 Kitties: Meezer, Bob, Mia and Dewey